Poultry Genetics For Small and Backyard Flocks: An Introduction

DNA (short for deoxyribonucleic acid)—The material containing the genetic instructions used in development and function of an organism. DNA is arranged in double helix–shaped strands. Gene—A segment of DNA that carries a blueprint for the function of a cell and, ultimately, a particular characteristic of an organism. Chromosome—A structure containing a complete strand of DNA. Chromosomes function in the transmission of hereditary material from one generation to the next. Chromosomes typically come in pairs, with one set donated from the mother and one from the father. Humans have 23 pairs of chromosomes. Chickens have 39 pairs. Genotype—The genetic makeup of an organism. Phenotype—The observable physical or biochemical characteristics of an organism resulting from its genotype. Examples of aspects of a chicken's phenotype include body shape, feather color, eye color, comb type, and so on.