1 Colored Egg Layer Chickens. The Araucana is a pure breed of chicken originating in Chile. 2  Ameraucana chickens were developed in the 1970âs in the United States from Araucanas. They were developed as a practical barnyard fowl that laid pastel shelled eggs, but without some of the limiting genetic factors related to rumplessness and tufts.
sex chromosome. a chromosome, differing in shape or function from other chromosomes, that determines the sex of an individual.
[Ã´â²tÉsÅm] any chromosome that is not a sex chromosome and that appears as a homologous pair in a somatic cell. Humans have 22 pairs of autosomes, which transmit all genetic traits and conditions other than those that are sex-linked. Also called euchromosome [yooâ²krÅmÉsÅm] . Compare sex chromosome. autosomal, adj.