Isnt (I hate contractions, I suppose a lot of women do too) it a fact that the ear tuft gene carries the lethal? And what about rumplessXrumpless.
The homozygous state (two genes) for Et (ear tufts) is lethal. But, I know of one bird that survived to adulthood for which breeding experiments confirmed that he was/is homozygous. Ear tufts are associated with other malformations of the head, particularly the ear. Since the Standard of Perfection for Araucana requires a trait that is lethal in the homozygous state, the breeders are always breeding Et / et+ birds to other Et / et+ birds or Et / et+ to et+ / et+. Breeding the heterozygotes to each other gives 25% Et/Et = dead-in-shell, 50% Et/et+ = tufted and 25% et+ / et+ = clean-face. To avoid all the dead ones, some people breed clean-face to hetero tufted: et+ / et+ cross Et / et+ ...this gives 50% hetero tufts and 50% clean-face and no homozygotes dead-in-shell. I know of a breeder that kept good statistics for several seasons and got a different distribution, but I attribute that to decreased hatchabilities in Et and Rp birds. A lot of beginners mistake beardmuff for ear tufts.
Thankyou Info. I was close with my reasoning,just needed a little backup
By Infomaniac on Monday, January 28, 2002 - 11:42 pm:
There are several kinds of rumplessness. Dominant rumplessness,Rp,like Araucana have, is known to cause reduction in hatchability, but it is not explicitly lethal. Lots of homozygous Rp birds are around. Most true Araucana are homozygous for Rp.
By Robbpa on Tuesday, January 29, 2002 - 12:00 pm: