Thoughts while Waiting on Joy (Nigerian Color Genetics)

As Joy's due date nears (end of June/early July), I am of course nervous, but I'm also really curious to see what her kids will look like! There is always that anticipation -- bucks or does? how many? -- but Joy's kidding presents a unique opportunity in the color genetics department. Joy is a black goat with minimal white, so genetically speaking she is only able to pass on black (or, very rarely, recessive red) and her white patches to her kids. That may sound boring, so if you're wondering what could possibly be so interesting about a goat who can only pass on the gene for black, let me explain:

Please bear with me here. I find genetics endlessly fascinating, but I will admit that they're a little over my head. So I'm going to avoid the fancy jargon for the most part. Not many people are familiar with those terms, and there's a very good chance I would use some incorrectly anyway. I'm not a geneticist, so let's just keep it simple for everyone's sake! First, I will try to briefly and simply cover the basics of what I'm talking about so that things make a little sense.

The Basics as I understand them: Each goat has two copies of a gene that determines their color or pattern, one from each parent. Recessive genes are genes that require two copies (one from each parent) in order to be visibly expressed on the goat. Dominant genes are genes that only require a single copy in order to be visibly expressed. If a goat inherits a dominant gene from one parent and a recessive from the other, the dominant gene will be the one to show up in the goat's appearance. These color genes are located on the "agouti locus," which is basically a place in the genetic code that holds the genes that determine color/pattern.

Other things like the specific shade of a color or whether or not the goat has white areas are determined by different genes in different places. For example, the buckskin pattern would be determined by these color genes we're talking about whereas the shade of buckskin (light, dark, mahogany, etc) and any white on the buckskin goat (spots, belt, overlay, roaning, etc) are not. 

What'cha hidin' in there, Joy?

So, about that black gene. In fancy terms, Joy has two copies of the black gene on her agouti locus. This is true of all black goats, because black is a recessive gene. That means that in order for a kid to be born black, both parents must have supplied a copy of the black gene. This is how I determined earlier this year that my buck Bazinga (a red chamoise) and my doe Sandy (a buckskin with white) both carry a copy of the black gene when they produced a black kid. 

This is also means that all black goats have two copies of the black gene, meaning that they can't pass on any other color. Black goats bred to black goats will always produce black goats, and any kid with a black parent is guaranteed to carry at least one black gene, which will be masked by another color unless they also inherit a black gene from their other parent.

Is your head spinning yet? Good, mine too. Let's continue!

Since black is recessive, that means that if Joy has a black kid, then Diddy (a buckskin with white) is also carrying a black gene. In addition, any other colors produced by the pairing must come from Diddy. Basically, whatever other color or pattern may be lurking behind Diddy's buckskin (which is a dominant gene, meaning that any goat that carries that pattern will express it), breeding him to Joy has the potential to reveal it. If they produce a gold kid, for example, then I know that Diddy carries both a buckskin and a gold gene. I don't expect that to happen -- I'm not even sure if it could, since I'm not sure if gold is dominant or recessive -- but I'm just using that as an example.

So what do I actually expect to happen?

Diddy, the daddy-to-be.

Well, I think I am most likely to get black or buckskin kids, probably with at least a little white since both parents are carrying white. However, since Diddy's sire is a chamoise, I would not be too surprised for that pattern to be produced, too. Diddy also has roaning, so that's a possibility as well. 

To be honest, I don't care if those kids come out green! I just want everything to go smoothly and everyone to be healthy. Heck, she can give me more bucklings if she wants. See if I care! Hah! 

In all seriousness, I just find it really interesting and fun to learn about genetics and to play the color guessing game. The more I learn about Nigerian color genetics, the more accurately I can guess. For example, I now know that if I breed Bazinga to a black goat, I will only get black or chamoise kids. (I should have known that already, since he has a black parent, but that didn't occur to me until this blog post...)

They still manage to throw curve balls, though, and I don't think we will ever be able to really predict what the genetics will throw our way when it comes to Nigerians! For example, this year I had two heavily roaned kids out of parents who showed no visible roaning at all. Go figure! 

I guess all that's left to say is this: if you want to know what colors are hiding in your goats, get a black goat for your breeding program (solid if you can find one!). And if you're interested in learning more about this subject, this article is a good starting place. In addition, this website is a great source for learning all the various colors and patterns of Nigerians.

We're all going to have a good laugh if Joy does have a gold kid...

Cheers