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.
48 gene-carrying intranuclear structures arranged as 24 pairs (23 identical pairs and one non-matched pair of sex chromosomes; male sex chromosome has 'X' and 'Y' components [XY]; female sex chromosome has two 'X' components [XX]); each pair of chromosomes reproduces itself during mitosis so that daughter cells each receive a full complement of 24 chromosome pairs; undergo reduction division during meiosis (i.e. ova or sperm formation) and each germ cell has only 24 single chromosomes (i.e ...