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.
In humans and other mammals, the sex chromosomes are X and Y. Females have two X chromosomes, and males have an X and a Y. Non-sex chromosomes are also called autosomes. Autosomes come in pairs of homologous chromosomes. Homologous chromosomes have the same genes arranged in the same order.