Gerbils have seven known gene loci. The genes at each locus occur in pairs. One gene comes from the mother and one comes from the father.
A combination of two dominant genes (ex. AA) or a dominant and a recessive gene (ex. Aa) at a locus will produce the dominant trait. A combination of two recessive at a locus (ex. aa) will produce the recessive trait.
The agouti locus, denoted by the letter A, determines if the gerbil will be non self-colored (
white belly) or self-colored (belly the same color as the rest of the fur).
The eye color locus, denoted by the letter P, determines whether the gerbil will have black or red (ruby/pink) eyes. The pp combination at this locus will also make the fur lighter.
The grey factor locus is denoted by the letter G. The gg combination at this locus lightens the fur color. It turns what would normally be a golden fur color to a grey, cream, apricot, or almost white color, and what would normally be black to slate.
The albino locus is denoted by the letter C. Gerbils do not have the albino gene, but if they ever do, it will be at this locus. The C gene is only dominant when the gerbil also carries the P gene. The c(h) gene at this locus causes the eye color to be diluted even further, even in combination with the C gene, as long as the pp combination is present at the eye color locus. It also will cause the fur color to be lighter. The c(h)c(h) combination overrides the P gene. This combination will produce a ruby eyed gerbil, but the fur will not be completely lightened. There is also a new gene at this locus, c(b), which is what produces siamese and burmese gerbils. Siamese gerbils are c(h)c(b). Burmese gerbils are c(b)c(b).
The extended locus, denoted by the letter E, determines whether the gerbil will have a full colored coat (with ticking) or if the coat color will be lightened (no ticking). The effects of this gene are dependent on the combination at the agouti locus. A gerbil having the AA or Aa and ee combination will have a golden fur color with no ticking and a white belly. The aa and ee combination produces the nutmeg gerbil--a self-colored gerbil with a yellow base fur and black ticking, the argente nutmeg/red fox gerbil--a self-colored gerbil with a reddish-gold fur, and the silver nutmeg/blue fox which is greyish-white with bluish ticking. There is another gene at that locus, the e(f) gene. The e(f)e(f) combination is what causes the fading color of schimmel and champagne gerbils. A gerbil that is ee(f) will be somewhat lighter than a gerbil that is ee.
The newest gene, just discoved in Germany, is located at the D locus, and is denoted by the letter D. The dd combination will produce a gerbil with a diluted fur color, due to clumping of pigments. For example, black is diluted to blue. The effects of this gene in combination with other genes are not known yet, due to the recent discovery of the gene.
The spotting locus is denoted by Sp. Spotting is determined by the presence or absence of the Sp gene. Gerbils which are Sp will be spotted. Spotted gerbils will have some white on their bellies, regardless of whether they are self-colored or non self-colored. Gerbils that do not carry the Sp gene will not be spotted. The SpSp combination is lethal. Gerbils with this combination are reabsorbed in the womb and are never born. Breeding two spotted gerbils will produce 25% less offspring as a result of this. 66% of the remaining offspring will be spotted and 33% will be non-spotted. Breeding non-spotted gerbils will always produce non-spotted offspring.
For more detailed information about gerbil genes, including a list of genes that are expected to be found in gerbils in the future and a table showing how common the genes are in different parts of the world, go to the NGS homepage. There is a link to that site on my links page.
More(charts included)
