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7.1: Fundamentals of Genetics

Introduction to Animal Science · LibreTexts

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    From LibreTexts, under CC BY 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Animal breeding, the application of genetic principles to improve the efficiency of farm animal production, is the science that has led to remarkable changes in animal species. Genetics, the very foundation of life, provides the mechanism to transfer traits from one generation to the next.

    An animal's genotype, or genetic makeup, establishes the potential for numerous traits, including disposition, coat color and type, speed, body composition, growth, reproduction, milk production, and disease resistance. The observable expression of the genotype into traits of economic importance forms the basis for an animal's market value.

    The genetic material of an organism is housed within the nucleus of each cell, organized into structures called chromosomes. These chromosomes are large molecules of deoxyribonucleic acid (DNA), and the smaller functional segments of DNA that provide the basis for inheritance are called genes. Collectively, the complete genetic material of an organism is termed its genome.

    DNA's structure consists of two strands wound together to form a double helix. Each strand comprises alternating sugar deoxyribose and phosphate bonds, forming the backbone of the molecule. Attached to each sugar is one of four nitrogen bases—chemical compounds classified as either purines or pyrimidines. The purines are adenine (A) and guanine (G), while the pyrimidines are thymine (T) and cytosine (C). These bases pair in a highly specific manner to form the rungs connecting the two strands of the DNA ladder: adenine always pairs with thymine (A-T), and guanine always pairs with cytosine (G-C).

    A gene, then, is a specific segment of this double helix composed of hundreds or thousands of nucleotides—the basic units consisting of a sugar, phosphate, and base. The precise sequence of these nucleotides encodes the information needed to build specific proteins, which ultimately determine an organism's traits.

    A colorful sculpture of a DNA double helix

    Image credit: Adam Knl from Pexels: https://www.pexels.com/photo/modern-...seum-31474398/

    This page titled 7.1: Fundamentals of Genetics was last modified on Sat, 02 May 2026 03:51:09 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Deanne Pawlisch.