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.
There are 22 pairs of autosomes and one pair of sex chromosomes. The sex chromosomes are the X chromosome and the Y chromosome. Sex Chromosomes: In human sexual reproduction, two distinct gametes fuse to form a zygote. Gametes are reproductive cells produced by a type of cell division called meiosis.