Agouti Mice and Obesity

by CucumberMouse Tue 02 Jan 2018, 9:12 pm

I read somewhere that agouti mice, or the mice with a more yellow coloring, and more brown colored mice (which I think are called brindle mice?) are more prone to be over weight or have obesity. From what I've read so far, it's because the agouti mice lack something called methyl. The more methyl a mouse has in it's genes, the less likely it is to become obese, and the more brown/brindle coloring it takes on. Doesn't this mean that brindle mice aren't overly prone to obesity due to their genetics, at least compared to how agouti mice are prone to obesity (I know all mice are able to get obesity)? I haven't done too thorough of research on this, so if someone could give a more detailed explanation of how the genetics of agouti mice affect their chances of obesity, it would be very much appreciated Very Happy

I'm having a bit of trouble wrapping my head around this, lol.

by River Tue 02 Jan 2018, 9:31 pm

Brindle mice are genetically linked to obesity -- in fact, obesity in mice is almost always genetic. I don't know the exact biology for this but the variety/color sticky might answer you better.

by CallaLily Wed 03 Jan 2018, 6:53 am

I don't have the answers either. Just going by what I've read from various groups that say brindle mice are prone to obesity (and sometimes yellow mice are mentioned too, but I always wondered if they were undermarked brindles). Out of the 12 pet mice I've had so far, the only ones to become overweight were 2 brindles and 2 agouti sisters. I've had black, chocolate, PEW, and RY but they all stayed within a healthy weight range for their build.

If you find the info somewhere else, please share! It would be interesting to know. Smile

by CinnamonPearl Wed 03 Jan 2018, 9:01 am

Im pretty sure agouti mice are not prone to obesity. Considering agouti is the wild type gene, that would mean bad things for the wild population... Right?

by CallaLily Wed 03 Jan 2018, 2:21 pm

I have wondered if Celyn and Rina were really over marked brindle. I'll have to dig back in my photos but I think their father was a broken brindle. Their mother was PEW.

EDIT: I didn't save any pictures of who was thought to be the father. But if I'm remembering right, he looked like an under marked broken brindle.

by CucumberMouse Thu 04 Jan 2018, 12:44 am

I'll go ahead and put the source I found here:

http://learn.genetics.utah.edu/content/epigenetics/nutrition/

There was another website but I'm having trouble finding it, I can't remember what I typed in to get to the website Rolling Eyes

But for the website I listed above, I was mostly paying attention to the "Eating for two" section, where it states "When a mouse's agouti gene is completely unmethylated, its coat is yellow and it is obese and prone diabetes and cancer. When the agouti gene is methylated (as it is in normal mice), the coat color is brown and the mouse has a low disease risk." When they say "brown mice" I'm assuming that they mean brindle mice, as I've seen several pictures that suggest a yellow agouti mouse and a brindle mouse being closely related, with the brindle mouse just being a yellow mouse with some gene altering it's fur color

I'll put one of the images here:

https://www.caymanchem.com/cms/caymanchem/cmsImages/figure2_id177.jpg

The info seems to contradict many of the members' experiences here, so maybe I'm just reading and interpreting all the info wrong? It'd be just like me to do that Neutral

by Peachy Thu 04 Jan 2018, 1:49 am

I think the agouti gene they're talking about there isn't the "wild type" coat color that we think of when we hear agouti. Brindle (Avy/*) is "Agouti viable yellow" and dominant over the wild type agouti (A/*) on the A-locus (Agouti locus).
All the mice in that picture are brindle. The difference in markings and color on those brindle/Agouti vy mice is where the methylation comes in.

Edit: This link doesn't get into epigenetics, but has some good information on the A locus and brindles:
http://www.informatics.jax.org/wksilvers/frames/frame2-1.shtml

Jax wrote:The most characteristic feature of the Avy allele is the variation in phenotypes associated with it ( G. Wolff, 1971). Some homozygous viable yellow animals when weaned are a reasonably clear yellow, indistinguishable from Ay/—, but many become sooty with successive molts ( Dickie, 1962a); some (homozygotes and heterozygotes) have a peculiar mottled pattern ( Plate 1-B; see also Figure 7-6b ), first observed when they are 4 or 5 days old, which may vary from a small black patch on an otherwise yellow coat to a complete intermixture of small black and yellow patches ( Dickie, 1962a); still others display a marked visual resemblance to agouti mice even though, on close examination, disparities are apparent ( Galbraith and G. Wolff, 1974). 4 The frequency of this "pseudoagouti" phenotype seems to be strain dependent ( G. Wolff, 1971).

At least that's how I'm understanding it. I might be misunderstanding the question. When my Lucas was changing coat patterns every few months I went nuts trying to figure out brindles. Makes my head spin. Confused