Saturday, December 31, 2011

To a Happy New Year

Image is copyright free from Wikimedia Commons

It's currently just under four hours until 2012 here on the East coast. Fireworks are already being shot off by those who are celebrating early. Of course, those of us with pets often must be concerned about the noise. I'm lucky enough to have a dog who isn't sound reactive, and who has only ever flinched at the sound of a cymbal crashing four feet from his head. He's never been bothered by fireworks, thunder, or the other loud noises that commonly scare dogs. By the way, 2012 will be the year that a certain handsome black Labrador turns seven years old. It's only a couple of weeks away now.

I hope everything goes smoothly for everyone else so that the you can ring in the new year without any incident. Here's to a 2012; may it be a good year for all. Celebrate and stay safe!

The Saga of the Cockroaches

This photo was taken this past June.
I have mentioned my pet Madagascar hissing cockroaches before (five different times, in fact). Those of you who remember any of those posts may have been wondering why I haven't mentioned them since October. Well, long story short: my colony collapsed. I wasn't very surprised when the adults died, since they were all old, but the babies? I made mention on several posts of losing one or two. Within two weeks of my last post they had all died. I still haven't quite figured out what happened. The terrarium was clean, bedding was fresh, the mites were down, they had plenty of food and water. The only thing that I can think might have happened is there may have been something growing on the water sponge. It was the only thing I hadn't cleaned recently. No matter what, I felt terrible when they were dropping like flies. And they're still gone.

My journey with the hissers started during my Junior year in college. I was taking Ecology and had to do some sort of experiment for my final in lab. After much thought, I decided to do an experiment to test for phenotypic plasticity. My test subjects were a group of fifty one-week-old baby Madagascar hissing cockroaches I obtained via my professor from her colony. When the month long experiment was over, I decided to keep one of the babies. That was who would eventually be known as Frankie. I wanted to have a group of all females, and we thought Frankie was a girl. I then picked up two adult females who I named Thelma and Louise. The other females (Lola and Brigite) I also obtained as adults, and Walter came later when I found out Frankie was a boy. I got them a nice terrarium, a sponge for water, and stuff to hide under. I was living with my parents at the time, and it took a lot of convincing to let me have them. I still couldn't get agreement to get some rats, but that's another story.

The first babies were born less than a month after I initially obtained the adult females. I hadn't thought about them being housed with males and coming to me gravid. I took them back to my professor, who was kind enough to take them. At that point, I thought I just had a few females and I might get a male some time in the future. Then, Frankie grew horns. Male hissers have prominent horns that are completely lacking in the females. I separated them for about six months, not wanting to end up with two hundred roaches. Then, I thought, why not? I got Walter and put them all in the same terrarium. That's not long before my first post about them began.

I don't know if I'll be getting more hissers. If I do, it's going to be a little while. I still have the terrarium and there's a store less than a mile away that sells them. They also have discoid roaches and some other very interesting critters. We shall see.

Friday, December 30, 2011

Mismark Case Study: Labrador Retriever

A gaggle of Labradors showing all three acceptable colors: black, chocolate, and yellow. Yellow can be in any shade of the red spectrum, from near-white to deep red. Chocolate can also vary. Image is from under a Creative Commons license.
Ebon is black with hints of red
Labradors, year after year recently, have been the AKC's most-registered breed. They are incredibly popular pet, and are also used for numerous working purposes, including hunting, tracking, and as service dogs. As those who read my blog regularly know, I myself have a Labrador, and he's a mismark to boot, though it's more subtle than most. The breed actually has a great number of mismarks that are seen:

  • Too much white
    • Anything more than a small amount on the chest isn't allowed
  • Tan points
    • In either black or chocolate dogs
  • Brindle points
    • In either black or chocolate dogs
  • Improper pigmentation
    • Where a yellow has a liver nose
  • Silver (controversial)
    • The blue dilution. Variations include "silver" (dilute chocolate, aka fawn/Isabella), "charcoal" (dilute black, aka blue), and "champagne" (yellow with a blue or fawn nose)

This yellow Labrador has a brown nose
Thanks to the restrictions provided by the standard,  Labs will usually be bred using color classes. Blacks are bred to chocolates and yellows are bred to blacks, but chocolates will rarely be bred to yellows. This is thanks to the fact that a brown nose on a yellow is not just frowned upon, but will actually disqualify a dog from showing. Usually, breeding chocolate to yellow is only done by those who breed their dogs for working ability rather than conformation. As such, brown-nosed yellows are most commonly seen in the more lightly built field-type Labradors and are rarely seen in the more heavily build show-type Labradors. As is so often the case, breeders of working lines could generally care less what the breed standard has to say as long as the dog can perform the required job.

This Labrador has too much white
One unacceptable appearance that constantly pops up in litters is too much white. Residual white happens all of the time in dogs that are genetically solid in color, which is why the mismark is present in every single breed out there that isn't supposed to have any white whatsoever. In Labradors, this is most often only a chest patch, but more extensive white can occur, spreading up the neck or appearing on the toes. The St. Johns water dog, a major ancestor of the Lab, had this amount of white as a standard occurrence. It seems odd to me that it is now considered unacceptable in the descendents. Interestingly enough, Bolo spots (white patches on the underside of the paws that are generally not visible when the dog is standing) are allowed.

This Labrador has tan points
Two mismarks that have been around for basically as long as the Labrador has been a breed are black and tan and black and brindle. Most Labs are dominant black (even chocolates and yellows) and dominant black can easily hide the recessives brindle and non-black/brindle that both allow the Agouti locus to show through. As such, two dogs carrying these recessives can easily produce black and tan or black and brindle puppies. Also, since the genes are recessive, carries aren't obvious until they throw a mismark. Even with selection, the colors simply aren't going to go away. In addition, there are other dogs like my Ebon with just a hint of red that may be very minimal black and tan and may go completely unnoticed, all depending on the amount of red that is distinguishable.

This Labrador is silver
Silver is a highly controversial color in the breed, thanks in part to the suspicion that the color was introduced through crossing with a Weimeraner. Whether it was that or a mutation: the color exists. Unlike a very large amount of people familiar with the breed, I don't really have much of an issue with silver existing in Labradors. However, I do disapprove of the breeding practices going into producing silver dogs, as well as the "charcoals" and "champagnes." It's inbreeding, pure and simple. It's a classic story: one or two dogs show up that are a desired color. Breeder wants to make more of that color and inbreeds like mad to produce a bunch of dogs that are the desired color. The blue dilution is recessive, and as such inbreeding is the only way to ensure the production of the color. This would be done through either only mating dogs that express the desired color or only matings dogs who are known to carry the color (and are thus related to that original population). Also, most silver breeders brag about their ability to produce litters that are guaranteed to have silvers and will charge heavy prices for the puppies of the desired silver color. There is usually no mention of the heavy inbreeding required to make the color possible. This is ridiculous, and does not bode well for dogs as all these people likely care about is profit.

Another practice I do not approve of when it comes to "silver" in Labradors is the mislabeling of colors. The AKC has advised breeders to register silver dogs as chocolate, when it fact the two colors are quite different. Silver, unlike chocolate, requires an additional gene for the color to be expressed. They also look quite different, with chocolate looking like, well, chocolate and silver looking like ash. The parent club doesn't support the practice of mislabeling, and neither do I. The two are different colors and should be identified as such. I hold the same position about all other breeds.

The Labrador retriever was originally meant to be a working dog: able to run and swim easily to go retrieve birds without breaking a feather. As such, color should not be a factor deciding what the breed should be. A dog with tan points is just as capable of retrieving a bird as a solid black one. If modern show breeds want to maintain that their dogs are still just as capable, why care about color? Why not stay true to what the breed once was? As I keep emphasizing, genetic diversity is of serious concern in purebred dogs. By disallowing certain colors, standards are only eliminating more and more diversity from the breed. Breeding for two separate types (show or "English" and field or "American") doesn't help either.

Thursday, December 29, 2011

Guess the Genotype #41

Can you guess this dog's genotype? His breed?

Image provided to me by J. Burns of Ghostfire Photography, and are copyright to him

Wow! 10,000 Views!

Ebon from today, waiting patiently for me to hive him the last piece of the ham bone (more on that later).
I want to give a special thanks to all of my regular readers, as well as those of you who drop by only once or twice.I never thought I would make it to ten thousand views, let alone achieving that many before the new year! I'm glad you all seem to be enjoying reading my blog. Here's some things that have happened in the past six months (and a bit):

Up to this point since the begging of the Musings on June 15, 2011, there have been 210 posts made (including this one). The blog has received 10,141 views from numerous countries, the vast majority coming from the United States and Canada. The URL has been changed once to make it easier for readers to find the blog, and the blog's overall appearance has changed several times. The blog has received over 150 comments from readers, reflecting mostly positive feedback. Interestingly enough, today I actually received my first spam comment.

I've started Graduate school and moved from the country to the city. I went from a house with two cats (Albus and Ginny) to a condo with two other cats (Jen and Ash). Ebon has had many new experiences, and re-lived some old ones. I've had some interesting experiences that have come from living in a city for the first time. My dad even adopted a new dog (Siggy). Overall, it's been a very fun six months! In the new year, I hope to have just as much fun.

Here's a few posts that will be coming to the Musings in the near future:

A Ferret of a Different Color (which I started and forgot about for months)
The Ham Bone
Why You Should Vaccinate Your Kids
An Uphill Battle: Tarter in a Kibble-fed Dog
The Eyes Have It
The Saga of the Cockroaches
Mismark Case Study: Labrador Retriever
..And much, much more!

Mismark Case Study: Dachshund

According to the AKC, Dachshunds come in two size varieties and three coat varieties. All of the six total types come in numerous colors and patterns. Pictured above are a red longhaired standard and a black and tan smooth miniature. Image is from Wikimedia Commons and is copyright free.
A chocolate and tan dapple Dachshund
Dachshunds are a breed that most people will recognize, even if they know them by some other name, such as "wiener dog," "dash hound," or numerous other labels. With that recognition usually comes a recollection of color as well, usually one of the two seen above, though more commonly black and tan. Despite this, the breed comes in quite a number of colors other than red and black and tan. Red, black and tan, wild boar, brindle, dapple (merle), and sable can all occur. The red seen in all of the dogs can vary from pale cream to dark red. In addition, the black can be diluted to chocolate, blue, or Isabella. Of course, not all combinations are considered acceptable, as is so often the case with breed standards, and there are additional colors that are also considered unacceptable. Here are the mismarks:

  • Improper pigment
    • In red dogs, pigment other than black is unacceptable
  • Solid colors other than red
    • May be solid black, blue, chocolate/liver, or Isabella/fawn
  • Piebald
  • A chocolate and tan piebald Dachshund
    • May occur in combination with any other color
  • Ticking
    • Only seen in piebalds
  • Dapple
    • When eye-rim pigment is lacking
  • Double dapple
    • Can only be produced by mating dapples together 

A red Dachshund with a liver nose
Clearly, when looking at what colors are and are not allowed, this breed is bred in color classes. Mainly this involves the breeding of red and black and tan. The black in black and tan may be diluted, but reds have to have black pigment. As such, breeding a chocolate, blue, or Isabella and tan, or even a black and tan carrying one of the dilutions, to a red increases the likelihood of producing a diluted red sometime in the future, depending on who is being crossed with whom. Even though there is no mention of color classes when looking at the parent club, color classes are standard practice in the dog breeding world where certain matings may lead to an unacceptable combination of colors. I have spoken of this time and time again in these case studies.

This Dachshund is solid black
I mentioned solid colored Dachshunds, which may come as a surprise to many. They do, in fact, occur, though there is some controversy surrounding the color in the breed. Some claim that the color only comes from breeders who may falsify pedigrees, and as such they may not be purebred Dachshunds. Another theory says the dogs are not truly solid black, but instead are very muddy black and tans. Others claim that breeding black and tans together generation after generation will cause the tan to disappear. The last theory does not hold up to closer examination, since countless breeds come in only black and tan and always breed true. It's highly unlikely that Dachshund tan points are inherited differently.  In any case, it does appear that recessive black may very well be present in the breed and thus the potential for solid chocolate, blue, or Isabella (as well as dapple and piebald without tan points). In addition, the color is still not acceptable according to the standard.

A brindle? double dapple Dachshund
Thanks to the presence of the merle gene in the breed, double merles can and do occur. As with every breed, double merle causes a very high likelihood of deafness, blindness, and/or other issues (up to and including a lack of eyes) occurring in the double merle individual. I am rather disheartened by the lack of recognition of this potential in the code of ethics. There is simply a mention elsewhere that double dapple is undesirable. There is absolutely nothing that would prevent a breeder from breeding two dapples together and no indication of a reprimand if the breeder produced unhealthy puppies from that breeding. In addition, there is nothing preventing mating of dapples to reds, which would likely produce cryptic merles. Cryptic merles are not known to be merles thanks to their coloring, and since the gene only affects black pigment, red dogs may very well have no signs of the merle gene. This makes it quite likely that an accidental merle-merle mating could be done, leading to a one in four chance of producing double dapples.

This Dachshund is Isabella and tan piebald
When it comes to piebald, the gene causing the color is a simple recessive and as such is likely to never be removed from the breed. Though most dogs that carry piebald will show some sign of it, usually through a prominent patch on the chest, this is not always the case. The patch may be quite small and look very much like the residual white that is very commonly seen in genetically solid dogs. White on the chest is acceptable, and as such it is quite likely that numerous dogs carry the piebald gene. Piebald isn't going to go away.

Several points on the Dachshund breed standard really don't make much sense when it comes to concerns about genetic diversity in a breed. Breeding in color classes splits a breed into chunks and narrows the number of possible pairings, isolating the breed from itself. By not allowing such combinations as liver-nosed red, this had produced a great potential for issues caused by this color class breeding. In addition, piebald has breed present in the breed for the entirety of its history. If piebald has been around throughout the breed's history, why isn't it allowed? If the breed is supposed to be the same as the badger hunter it once was, why does color even matter?

Wednesday, December 28, 2011

Tuesday, December 27, 2011

Invasive Species: Feral Pig

Feral pigs are also known as feral hogs and razorbacks.
Feral pigs are a major issue in numerous parts of the world. They are virtually everywhere, and may be more of an issue than reported as some sources may think the pigs are of no concern. In fact, feral pigs can be a serious problem. Due to their omnivorous nature, they eat virtually everything, uprooting anything in their path. This destroys crops and countless food sources used by other animals. They may be nocturnal or diurnal and live in virtually every type of environment. Many feral pigs are descendents of domestic pigs gone wild and it's amazing what that process does to the animals. Feral pigs are more like their wild hog relatives, with long snouts, straight tails, lean bodies, and shaggy hair forming a prominent ridge along the back. This patch of longer hair is the origin of the common name "razorback."

Pigs were often purposefully introduced to areas for use as a food source, either as semi-domestic animals or for use as game. As such, it was common for explorers to leave some behind after they discovered a new location. Sometimes pigs would escape, but in almost all cases the ancestors of the feral pigs seen today were purposefully released. Part of this is thanks to some of the methods used to feed the pigs: namely letting them run free and having them find their own food.

When it comes to managing pig populations, there are numerous methods used. Poisoning is one of the most common as it is the most cost effective. However, as with any poisoning, there is a high risk of poisoning species other than the one being targeted. Also, pigs are known to vomit up certain poisons, making them less likely to actually kill the pig. Trapping is also done, after which the pigs will generally be destroyed rather than relocated. Since they are such mobile animals, it's unlikely simply moving the pig will be helpful. Hunting is also quite common, with various methods being used. Hunting pigs with dogs is one of the most commonly used methods.

Despite their extremely destructive habits, pigs do have their uses. Aside from being a source of food, they were once traded for money or goods. They can help control larvae of some damaging plant parasites. They were also once used to clear and aerate soil for gardens.

Feral pigs are on the list of 100 World's Worst Invasives at #91

Image is from Wikimedia Commons and is copyright free. 

Sunday, December 25, 2011

Even More Adventures

I took Ebon out to yet another park (this one by my parents' house) on Christmas Eve. He's been there before, many many times. Part of the reasons for it was the need to break in his new pack a little bit.
Happy Ebon on a fifteen foot wooden overlook that provides a nice view of the marsh. There's a nice three mile path encircling the marsh. Ebon loves his pack! I'm slowly working him up in weight, and six-and-a-half pounds didn't phase him. To get to the overlook Ebon had to climb stairs. I still remember when he used to be afraid of stairs. Taking some time, making them fun, and providing lots of praise and cookies made all the difference.

This sign is there for a reason!
My father and Siggy came along as well. We had fun and the dogs came home tired. The park used to allow dogs off leash, but doesn't any longer. I wonder sometimes why they made that decision. Unlike many of the other parks, this one is in a rural area and there is little risk of dogs running into streets or bothering people in their homes. However, there are always the alligators. And the snakes, including several venomous species. I don't think anyone wants their dog getting injured by either one of those reptiles. I have seen both at this park on numerous occasions, including a couple of very sizable alligators. One of which was at least seven feet. However, winter sends them into hibernation so it's far less likely to come across one.

Guess the Genotype #40

Can you guess this dog's genotype? What about her breed?

Image is from under a Creative Commons license

Friday, December 23, 2011

More Adventures

Today I went to another park with my parents, along with Ebon and Siggy. It was the "big park," as I'm going to be referring to it. It's the biggest park in the city.

Ebon by the beautiful big fountain in the middle of the park. It was drizzly while we were there.
Of course, we had to get obligatory pictures by the fountain. I felt like such a tourist, but it was one of those situations where we've lived here so long but never got around to going there. So, now there's proof that we finally went. It's quite a nice park, with wide expanses of grass, tennis courts, a playground, a concert pavilion, restaurant, and lots of sidewalk that the local runners love. There is a very broad sidewalk that cuts the park in half long ways, flanked on both sided by live oak trees dripping with Spanish moss. The decorations for Christmas were simple and attractive. The park is constantly getting dressed up for holidays, and they even dye the fountain green for St. Patrick's Day. Dogs must be leashed, but apparently old ordinances allowed dogs to be loose if they would come when called. I was surprised by how many people were ignoring the new leash law. Ebon's very good, but I still don't trust him that close to busy streets (which border the park on all sides) as he has basically no experience with them and I don't know if he would try to run across one.

Ebon in front of the concert pavilion, and another fountain, looking toward Siggy. The playground is to the left.
Siggy by the fountain
We had a nice little time, walking the length of the park and just kind of taking it in. Ebon had a blast, as he always does in new places. Unfortunately, he got a bit foamy today. It was very humid and I couldn't find a source of water available to him for most of the distance, poor fellow. He did okay, though, and was able to get a drink out of a water fountain that actually had a spout clearly meant for dogs, seeing as it was only a foot off the ground. Unfortunately, Siggy didn't have as much fun as Ebon did. He's a bit sensitive to certain noises and he spooked three different times while we were there. My father informed me that he is especially upset by the noises of small children, since they tend to squeal. We walked near the playground and Siggy froze when a child screamed, tucking his tail and doing the exaggerated licking motion that anxious dogs do. My father had to do a lot of coaxing to get him moving again. Clearly, Siggy needs some work to try and get him to be calmer. My father loves to run, and has taken Siggy to several public running events already. As such, Siggy's uncertainty involving certain noises is of concern. With time and cookies, hopefully Siggy's confidence will get a boost.

Ebon by the tennis courts. It was very quiet thanks to the dreary weather. For a size comparison, the pavilion in the distance is about forty feet high or so. The central sidewalk is to the left under the row of trees and beyond that is a green space of approximately the same size as this one. The fountain in the first image is past the pavilion. Of course, Ebon was looking right at me until I hit the shutter. It seems I always end up getting pictures of him getting distracted by something.

Thursday, December 22, 2011

Mismark Case Study: Dalmatian

Dalmatians in their two accepted color varieties: black spotted and liver spotted. The central dog is liver, while the other two are black. Image is copyright free from Wikimedia Commons.
This Dalmatian? has a large patch and indistinct spots
Dalmatians have a very distinctive appearance, and their color standard has a quite narrow range of what is considered "acceptable." The spotted coat is caused by the combination of two genes: extreme white piebald and what is believed to be a modified form of the ticking gene. This is why the puppies are born white and the color appears later. This is also why patches will appear (where a puppy is born with some color), all caused by the extreme white piebald gene not removing all of the color from the body. Both acceptable colors are caused by the dominant black gene, thought the liver dogs are also expressing the recessive liver dilution. Due to the dominant nature of the black, there is a great amount of potential for mismarks. In fact, quite a remarkable number of mismarks are known in the breed, almost all of which are caused by recessive genes:

  • Lemon 
    • Moderately pale to very pale recessive red
      This Dalmatian is a lemon mismark
  • Orange
    • More red-ish recessive red
  • Blue
    • Diluted black
  • Fawn
    • I don't know if it's been documented
    • With blue possible, fawn (blue + liver) is possible
  • Tricolor
    • Tan spots in the same regions seen in tan pointed dogs
    • May be black or liver (potentially also blue or fawn)
  • Brindle
    •  Stripes on red, of course 
    • May be black or liver (potentially blue or fawn)
  • Trindle
    • Where stripes are seen in the points 
    • May be black or liver (potentially blue or fawn)
  • Sable
    • Has the potential for black, liver, blue, or fawn pigment
  • Indistinct spots
    • Spots with edges that aren't crisp
  • Improper eye-rim pigmentation
    • Pink either in part or in full
  • Too few spots
    • Very few or no spots 
  • Too many spots
    • When the spotting is too heaving 
  • Patches
    • Present from birth

This Dalmatian has too many spots
Since the cause of nearly all of these mismarks are recessive genes it is nearly impossible to remove the color from the gene pool. As such, they continue to appear. Some of the variations may even be considered rather common, while others are more unusual. However, it is quite remarkable how many variations are frowned upon, especially when it comes to such things as patches, the density of the spots, the distinctness of spots, and eye-rim pigmentation. By the nature of the two genes that go into making a dalmatian a dalmation (extreme white and ticking), all of these variations are not just very possible, but almost expected. Even all white dogs, since ticking/spotting is dominant, a dog without the spots is quite possible. Eliminating dogs who express these unacceptable variations from the population by not breeding from them is basically a pointless endeavor. The variations are common because some of what goes into the density and placement of the spotting is random chance. This is true of both the extreme white and the modified ticking. As such, eliminating the dogs from the breeding population will not prevent the undesirable phenotype from occurring. Removing these dogs only serves to decrease the genetic diversity in the breed.

This Dalmatian has incomplete eye pigment
The require for completely pigmented eye-rims is rather ridiculous, in my opinion, as extreme white piebald, by its nature, will cause a loss of pigment all over the body. As such, it is very common for the gene to cause a loss of pigment from the skin as well as the coat. In truth, part of what may cause so many Dalmatians to have black eye-rims is the presence of those spots. They grow from dark spots on the skin, and as such dogs with black spots around there eyes are more likely to have fully black eye-rims. However, chance may very well lead to a dog with virtually do face spots and completely pink eye-rims. It seems silly that the standard allows blue eyes but not pink eye-rims.

As I have mentioned time and time again in these case studies, frowning upon a dog just based on its color is absurd. Especially if the differences are minor, and even more so if the variation is a common one and occurs due to the nature of the genes that go into the making the breed's acceptable standard colors. Even worse, dropping these dogs needlessly narrows genetic diversity in breeds that already have serious inbreeding problems thanks to closed registries and heavy selective breeding.

Wednesday, December 21, 2011

Unusual Breed: Porcelaine

Two Porcelaine dogs in Poland. This breed is also known as the Chien de France-Comté

The Porcelaine is one of the remarkably numerous French hound breeds. It is classified as being a medium-sized hound breed and is meant to hunt smaller game. I find it intriguing that the FCI standard actually includes a statement that the general appearance of the dog is "very French looking." Other interesting points follow, such as the requirement of a "sweet" expression, the movement being "lively and gay," a descriptor of a tail hair fault being "like ears of grain," and the reference to the characteristics of the ears by using the term "leathers" but never referring to them as ears. Some characteristics of the hound are meant to be quite distinctive, such as a mostly white coat meant to resemble porcelain, thus the origin of the name. The skin is meant to be speckled, and the ears should be ticked. Dogs range in height from twenty-one to twenty-three inches and in weight from fifty-five to sixty-two pounds.

Once a popular pack hunting dog, the breed's popularity dropped after the revolution of 1789. In fact, it is thought that the breed may have even died out in France. Swiss breeders either restored or re-created the breed, using the last of the dogs originally of this type and mixing in other hounds from Switzerland. Today, the breed is not common and it is mostly restricted to the countries of Switzerland and France. The Porcelaine is thought to be a partial ancestor to the American hounds. I wasn't able to find any information on the breed's health beyond a statement on Wikipedia that proclaims that it is prone to "general dog issues." I suspect this means such common conditions as hip dysplasia are seen.

Sources are the Fédération Cynologique Internationale and Dr. Bruce Fogle's The New Encyclopedia of the Dog. Image is from Wikimedia Commons under a Creative Commons license.

Tuesday, December 20, 2011

Heterochromia: Types and Causes

This woman has heterochromia,with one brown eye and one hazel eye.
Complete heterochromia
I introduced heterochromia recently by discussing its presence in dogs. Now, I will be going over it in a bit more detail, especially its existence in humans. Specifically, I speak of heterochromia iridis (also known as heterochromia iridum), which refers to the coloring of the iris of the eyes. Technically, heterochromia (or "different color") may refer to other parts of the body as well, such as hair, fur, or skin.

There are multiple ways in which heterochromia can be classified (and the classification I give here may be revised in the near future). There is complete heterochromia, where each eye is fully of one color. So, for example, one eye is blue and the other is brown or one eye is amber and the other green, among numerous other possibilities. This can be either inherited or acquired, with the acquired form having numerous different causes.

Sectoral heterochromia
Central heterochromia in my own eye
There is also incomplete heterochromia, where the difference in eye color is not so distinctly defined. Incomplete heterochromia can further be broken down into types. The two types are central and sectoral. Central is where the iris has a central ring that is differently colored than the rest of the eye, such as a brown ring in an otherwise green eye. Sectoral heterochromia, on the other hand, is where a section of the eye is a different color than the rest, with no rhyme or reason to the placement, such as a brown flash in an otherwise blue eye. Again, incomplete heterochromia has a number of possible causes.

Causes are incredibly varied when it comes to heterochromia. When the condition is present from birth (congenital), it is overwhelmingly likely that it is an inherited trait in some form or another. Any of the types of heterochromia can be congenital. Sometimes the inheritance is obvious (such as another family member having the same trait), but other times it is not. Familial heterochromia (there the trait is inherited and runs in a family) is a rather common explanation. Others are partial albinism (complete absence of pigment in a small area of the body), piebalding (a form of dominant lack of pigment sometimes seen in humans), and the potential for congenital heterochromia to be caused by mosaicism (mutation) or chimerism (fusion of twins early in development).

I suspect Jen's dark spots are from injury
Heterochromia can also be acquired, with the possible causes being quite numerous. One possibility is injury. Injury to the eye can case numerous types of alterations, including heterochromia. Blood vessels in the iris can leak or hemorrhage after trauma, causing potential for a permanent change in eye color. Central heterochromia can be a sign of high levels of toxins in the body.  Numerous medical conditions can also lead to a partial or complete change in eye color, such as glaucoma (sometimes through the medications prescribed for treatment), neurofibromitosis, eye inflammation, foreign bodies, and numerous other conditions and syndromes. Some of the syndromes have other symptoms which are far more important than heterochromia, as they can be far more dangerous.

A cat with complete heterochromia
Many animals commonly will have heterochromia, while the condition is unusual in humans. Horses, cats, and dogs all have relatively high incidences of heterochromia, generally in combination with a certain color phenotype. As I mentioned in my previous post, dogs will have the condition most often in combination with the merle or white spotting genes, but also can have the color inherited independently. Cats that are mostly white (through the white spotting gene) or completely white (through the dominant white gene) are usually the only ones that will be seen with heterochromia, but this is not always the case. In horses, heterochromia is most commonly associated with pinto markings. Certain other animals, such as cattle, are also know to exhibit heterochromia.

EDIT: I forgot to add to this in. There are numerous celebrities nowadays who have heterochromia. Some are more famous than others, but all have fascinating eyes. Mila Kunis, Christopher Walken, Kate Bosworth, Dan Akyroyd, Max Scherzer and Jane Seymour all have heterochromia of various types, just to name a few. David Bowie is thought by some to have heterochromia, but in fact has a permanently dilated pupil.

Sources are Right Diagnosis, Sewanee University of the South, PubMed Central from the National Center for Biotechnology Information, Miles Research, h2g2, University of Maryland Medical Center, Indian Journal of Ophthalmology, and Wikipedia. Images except for my eye and Jen's eye are from Wikimedia Commons under Creative Commons licenses: one, two, three (mine), four, five (mine), six.

Sunday, December 18, 2011

Ebon's Got a Brand New Pack (and other things)

Ebon watching people walk past during lunch. He was a very good boy.
I took Ebon downtown for the first time today. He has been into the middle section of the city and the area where we live now, but he had never gone downtown before. We had a nice walk, traversing a good portion of the city, including eating lunch at one of my favorite restaurants, where the pictures were taken. We also went down to the river. It is one of the oldest parts of the city and has a long stretch of sidewalk along the water. Unfortunately, he had a little too much fun chasing sparrows. The sparrows (and pigeons as well) are only really found downtown, and since it was his first trip he had never seen them before. He's always had a great interest in birds (he is a bird dog, after all), but it's a bit embarrassing when he almost trips me while darting over to go investigate. I think I need to work with him on that.

At the restaurant again. He was a bit startled when a semi truck drove by, but otherwise was calm. .
The city is rather dog friendly, and many businesses allow dogs inside. Numerous restaurants have tables outside so that you can eat with you dog present, like the one we went to. All of these places will offer water to your dog, which is a necessity since it can get so very hot here. It was fairly cool today, barely hitting sixty degrees. The weather was perfect for a nice long walk, though it did get a bit chilly in the shade.

One other things we did while downtown was get Ebon a new pack! There's an outdoors store downtown that has a fair selection of dog things among the people things. I caught sight of their dog packs, including the fact that they had Ebon's size for once, and decided to buy one. As part of this, I thought I would do a summary of the different packs and things that he now has.

I purchased Ebon's original pack about four years ago now. It's an old Outward Hound backpack in size X-Large and is actually the first saddlebag-style dog backpack I ever remember seeing. I actually had to go to some lengths to find one, eventually finding a seller on Amazon. You can't find one new anywhere now, so it seems. The stores all seem to be carrying the newer, though similar, style being manufactures by the company. The reason I chose to get it was cost reasons. It was the cheapest one I could find at the time at around $25. However, I have never been very happy with it. There are several downsides, such as an awkward fit and one of the straps being extremely close to his line of urination (it has gotten wet and required cleaning). It does serve its purpose, but is far from ideal. Now that I have a replacement, I think I'm going to pass this one on to my dad's new dog, Siggy. If nothing else, it'll get Siggy used to carrying a pack if my dad ever does want to go hiking with him.

Ebon's old pack loaded with four liters of water, nearly nine pounds in weight. Notice the pressure being placed on his spine? This is the main reason why I wasn't completely happy with this pack. Anything more than four or five pounds and it starts getting uncomfortable for him. The maximum weight he should carry is about twenty pounds, so five is a paltry sum in comparison.
A vast improvement is the pack that I purchased today.  It's a Ruffwear Approach Pack and the difference between the two packs is rather astounding. The new one is a better fit by far, though slightly more difficult to put on (it requires a leg to be slipped through a loop). It's significantly easier to adjust the size on and shifts much less after its been adjusted to the correct fit. Also, none of the straps dangle, so there's no risk of him peeing on them! The weight distribution is clearly superior, and a cutout in the back seems to be releasing pressure from the spine in the same way that a saddle tree does. Unlike with the Outward Hound pack, Ebon showed no discomfort after it had been weighted. In addition, there is plenty room for things to be clipped to the exterior of the pack via specially-made loops like those found on human packs (unlike the flimsy plastic loops on the other pack) and the leash loop is sturdy metal rather than plastic. I never used any of the loops on the old pack because I knew they would be broken if I had tried. Though the Approach Pack isn't meant for long hikes, I think it would be sufficient if you packed right. I'm sure I could make it happen. I paid the full $75 for the size Large, but I think it's worth every penny because of its quality.

Ebon's new pack holding the same four liters/nine pounds. Notice the complete lack of pinching on his spine! Unlike the old pack, I might even feel comfortable enough to put a full twenty pounds in there. I do wish I could have found it in blue for old times sake, but the green is quite attractive.

Last, but not least, is Ebon's vest. I have mentioned it before and show pictures of it as well (twice), but I haven't spoken of it in detail. I purchased it some time ago after having a close call with a car while walking Ebon at night. Since he's so dark, he's nearly impossible to see at night. I did get him a reflective vest when he was a puppy, but he soon outgrew it. So, after some hunting, I came across the PooBoss K9 Unility Vest. Though I don't think I'll ever make Ebon carry his own poop, the vest's other uses are great. It's perfect for a walk or a short hike, making him easy to see and also allowing easy carrying of poop bags and other small items, such as keys. I also hope to one day get Ebon certified as a therapy dog, and it would be a great medium for patches proclaiming him as such. I could also see its use for service dogs for the same reason. I was able to buy it on sale for $20. It's available in multiple colors and sizes, quilted and non-quilted linings, and you can even get free shipping through Amazon through Amazon Prime. Ebon wears size X-Large, and it fits him perfectly.

Ebon loves his vest, and darn is it ever reflective!

Saturday, December 17, 2011

Crazy Plants: Duckweed

Duckweed in Spain
Duckweed is a quite unassuming-looking plant that is commonly seen floating on the surface of ponds and lakes. Believe it or not, one species is actually the smallest flowering plant known and is thus worthy of note. There are numerous species which can vary quite a bit in size The structure is simple, with one to three small leaves, each with a small root hair. It can reproduce both sexually and asexually,

The plant is generally considered a pest species. If not kept in check it can actually become a serious issue. If the pond is completely covered, photosynthesis cannot occur and this oxygen levels will drop in the water, leading the death of any fish or other aquatic creatures present. To help prevent this from occurring, there are a wide variety of products and methods used to control the plant. One of the basic methods is simply removing the plant by hand, but this will not eliminate it. Ducks and carp (including koi) are effective biological controls, as both will eat duckweed. Chemical methods can also be used, with some being more effective than others. Preventive measures can also be taken to prevent duckweed from becoming a problem in the first place.

Despite this, duckweed has the potential for doing a lot of good. It is being promoted by the UN for use as a food for poultry and other animals, particularly ducks. It is cheap to produce, and thus can be a quite quite useful component of animal feed.

Sources are Ohio State University, Texas A&M University, and the Food and Agricultural Organization of the United Nations. Image is from Wikimedia Commons and is copyright free.

Friday, December 16, 2011

Mismark Case Study: German Shepherd Dog

German shepherds are most commonly come in four colors: sable, black and tan (saddled tan), bicolor (tan point), and black. Sable and black and tan are seen in the above dogs in the order sable, black and tan, sable. Image is from Wikimedia Commons under a Creative Commons license.
According to the AKC, virtually any color of German shepherd is fine except for white. However, on further examination of the standard, it can easily be seen that this is really not the case. To begin with, liver and blue are serious faults, and as such are unlikely to show up in the show ring. On top of that, eyes are supposed to be quite dark, and the liver and blue dilutions will produce dogs with pale eyes. If these two points fail to keep these colors out of shows, this will: a nose that is not black is a disqualification. Though blue can appear near-black in color, the lack of pigment produced by the dilutions causes noses to be non-black. Thus, there are quite a number of colors deemed "unacceptable" than would be expected from an initial examination of the standard. Here's a list of some mismarks:

  • White
    • Varies from pure white to biscuit/cream
  • Blue
    • May be in combination with any color, replacing black with blue
  • Liver
    • May be in combination with any color, replacing black with liver
  • Fawn
    • Blue and liver dilutions combined
    • May be in combination with any color, replacing black with fawn
  • Panda (a new mutation that causes Irish white-type markings)
    • May be in combination with any previous color
    • Though not specified as a disqualification, it is generally considered "unacceptable"

This GSD is white
Since the German shepherd is such a popular breed, the mismarks have proven to be rather popular colors, particularly the white and panda dogs. Since the colors are undesirable, the movement has been to produce independent breeding populations of the specific color. As with and splitting of a breed, this is of great concern. By isolating the dogs of these specific colors from the general population, it narrows the gene pool and leads to the potential for a marked increase in the health problems seen in the newly formed breed. This is more true for the white dogs than the pandas due to the recessive nature of the gene. Inbreeding is required to keep the color going, and this only narrows the gene pool further. Though out crossing to more traditionally colored dogs was likely done to expand the gene pool, this only does so much. Since the breed is now accepted by several registries as being separate, this basically prevents any more crossing between the two populations from occuring.

One of these GSDs is liver
Another major issue I see with the German shepherd standard is the dislike of the dilute colors. This breed is touted as a working breed and highly capable. Putting aside the weak hind ends and other traits that would impede working ability so often seen in show lines, why should color be a point of concern in a working dog? It makes no difference if a dog is black or fawn: if it can do what it was meant to do, then that is all that should matter. Having an all white coat will not prevent a dog from being able to protect its master or sniff out criminals.

Thursday, December 15, 2011

Guess the Genotype #38

Can you guess this dog's genotype? What about its breed?
Image is from under a Creative Commons license.