Thursday, February 14, 2008

Black or Red or ......

There are 3 basic coat colors. There is Black, there is Red and there is the Wild coloration. Black, is of course, black, Red is red and the Wild coloration is a combination of red and darker colors. Animals may look almost black, brown or mostly red. They generally have darker areas on the face, neck and/or legs. Bulls will usually be darker in color than females.

Keep in mind that unless an animal is albino (has NO pigment) they always have a base coat color that is one of the above. It may be diluted, or disguised, but it is still there, and will be passed on. It may be hard to tell what the base coat color is, but there is always a base color.

Ed is considered black, E+ is considered wild and e is considered red.

Ed is dominant over E+ which is dominant over e.

Any animal carrying E will be black in color. It doesn't matter whether they are EdEd, EdE+ or Ede, they will be black. But when it comes to passing on genes, only EdEd will always pass on Ed. The other two will pass one either E+ or e 1/2 of the time. This is where the surprises come in. That black cow bred to a black bull, that throws a red calf for example.

This animal is Ede. We know this since she has had a red calf in the past.

This animal is EdE+. Again we only know this because she has produced calves with wild type coloring. She has also produced black calves.

To the best of our knowledge, this cow is EdEd. She has only produced black calves in the past, regardless of what she was bred to.

E+ animals will be black if they also have the Ed. However if the animal is E+E+ the animal will be wild colored, that is be reddish, to brown with darker areas on the head and neck. E+e animals will be very similar to E+E+, although they may be somewhat more red. They will still have the darker areas on the head and/or neck.

Here is a cow that exhibits the wild coloration. Notice the darker area on her face. We do not know if she is E+E+ or E+e, although I am inclined to believe she is E+e.

ee animals will ALWAYS be red. They are homozygous for red and cannot be any other color. They can only pass on the e gene. However, you must remember that if e is in the prescence of either Ed or E+ you will not necessarily see it. Again, this is where those surprise red calves come from!!

This animal exhibits the ee. She is red in color, and only red. She can only pass on the e gene.

Now remember, that the other coat color genes work on top of the base color. As stated earlier, the base color may be diluted or hidden. There are genes that produce patterns, spots, dilutions and stripes. Some will make an animal appear white, or tan or grey. There are genes that place spots of color inside of white areas. But there will always be a base color, with the exception of an albino where the pigment is completely removed from an animal, and this includes eye pigmentation.

The Basics of Genetics.

Genetics follow some basic rules.Firstly there is always 2 genes that work to express a trait, each trait has its own locus. A locus is defined as a place on a chromosome where a gene is located. There may be more than 2 different genes that can be located at a given locus.

Some genes are dominant, some are recessive. Dominant means that if that gene is present it will express itself, it only takes 1 copy for a dominant gene to be expressed. Recessive means that in order for a specific trait to be expressed there must be 2 copies of that gene. Some genes are both dominant and recessive. There are genes that are incompletely dominant. What this means, is that if there are 2 copies the trait will be expressed more fully and, when only 1 gene is present the trait will be expressed, but to a lesser degree.

Once you understand that 2 genes are required to express a trait, the next step is to understand Homozygous and Heterozygous. Homozygous means that there are 2 copies of the same gene at a certain locus. Homozygous therefore means that the animal can only pass on one type of gene from that particular locus. Heterozygous, on the other hand, means that there are 2 different genes located on the same locus. Heterozygous means that the animal has a possiblity of passing either one or the other gene on.

The other big thing to understand when talking about genetics is that each parent passes on 1/2 of its genes to each offspring. There are many different combinations of genes working together to make an individual what it is. There for there are many different combinations of genes that can be passed on. It all depends on what genes are in the 1/2 that get passed on.