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.
Sex linked gene. gene located on the X or Y chromosome. fathers can pass sex-linked alleles to all of their daughters but to none of their sons, mothers can pass to both sons and daughters. iN humans sex-linked gene refers to a gene on the X chromosome.