Tell me about red genetics

[karenp]

I see two kinds of red, the black nosed, which I think are really cute and the tan nosed ones, not so cute in my opinion. I also know there are two types of red; gene wild and the other one. How are these related to the tan/black nose phenotype? Is one dominant?

If I wanted to specifically breed for black nosed reds, how would I accomplish that?  (I don't have the room for that kind of breeding, just interested)

[cascade]

Chromosomes are the structures that hold the genes that code for the features of animals and plants, including color.

Each location (locus) on the chromosome controls a different feature. Each locus has a number of alternative gene choices - these alternative gene choices are sometimes referred to as "alleles".


The Extension locus controls the extent of black pigment and red pigment available to the animal.

There are several alternative genes that can occur at the Extension Locus

ED (Dominant black) = lots of black pigment
E+ (wild type) = ability to work with both red and black pigment
e (recessive red) = mostly just red pigment


Black-nosed reds need an E+ gene at the extension locus, to give them the ability to work with both red and black pigments.

Several other loci and the possible genes located at those loci, have an effect on the placement of red vs. black pigment, creating patterns. These other genes that code for patterns need to have both red and black pigment available in order to create patterns. So, for an animal to have certain patterns of red and black, they need an E+ gene at the extension locus plus pattern genes at other loci.

One such pattern locus is the Agouti Locus... Genes at that location are primary patterning genes in many species of animals. The Agouti Locus genes are well studied in some species, but not yet well studied in cattle.

The possible Agouti alleles (gene alternatives), may be something like this

A+ = wild type = pattern found in extinct wild ox

Ax = solid red with no black shading

Ay = solid red with black nose.

Then, to complicate things, the genes at each location come in pairs, one gene of the pair from mom, and one from dad.

So if you want a solid red with a black nose, you may need one of the following:

E+/E+ Ay/Ay

E+/e Ay/Ay

Other Agouti combinations may also work.

There are no DNA tests available yet for the Agouti Locus genes in cattle

[cascade]

Here is what E+/E+ A+/A+  (wild-type red  and wild Agouti pattern) likely looked like in the Aurochs, wild ancestor of cattle

[karenp]

So, to get black nosed red you need a red phenotype*and homozygous Ay, similar to dun where you need black phenotype and homozygous for the dun gene.

*I know it needs to be homozygous to get red.

So, if you bred two black nosed reds, you would always get black nosed red? Or, not if they both carried recessive red?

[cascade]

It's likely that some black-nosed reds are homozygous for the genes required, while other black-nosed reds are heterozygous for the genes required.

So if you bred two homozygous black-nosed reds together, then you would get 100% black-nosed red calves.

But if your two black-nosed reds are heterozygous for those genes, then you might get lots of black nosed reds, and also some pinkish nosed reds as calves.

[cascade]

Here's one of my black-nosed red bull calves born last year.  His sire was dark red, with a pink nose.  His mother has a darker nose, but not a black nose.

[jamshundred]

Kirk,

Please put the pictures smaller.  Geez, you are like a three-year old.  Do you never listen?   Use the attachment button and ad your photos.  .. it won't allow for the largeness.

About the red, Karen.  I was going to refer you to Gabriella Nanci's website where she has information on colors that is easy to read and understand but Kirk is doing a good job.  If you still have questions I will get the website address.  

Judy

[karenp]

He looks like he needs a hug.

Judy, why are large pictures a problem?

[cascade]

I don't actually post any pictures, I just link to existing pictures already stored out on the internet.