Introduction to Genetics and Livestock - Flashcards

20 flashcards covering key concepts from Ch 1 & 2 of Livestock Genetics.

What is Genetics?

The branch of biology dealing with heredity and variation among plant and animal species.

What is a Trait?

Any observable or measurable characteristic of an individual.

What is Phenotype?

An observed or measured level of performance for a trait.

What is Genotype?

Genetic makeup of that individual.

What is a Chromosome?

DNA-containing structures in cells; composed of segments called genes.

What is a Gene?

A short segment of a chromosome; directs synthesis of proteins or performs regulatory functions.

What is a Genome?

The entire genetic material of an animal.

In the equation P = G + E, what do G and E represent?

G = genotype; E = environmental effects.

What is a Biological Type?

Classification for animals with similar genotypes for traits of interest.

What is Genotype by Environment Interaction?

The dependent relationship between genotypes and environments in which performance differences between genotypes change across environments.

What is Mendelian Inheritance?

Law of segregation and independent assortment.

What is Hardy-Weinberg?

Population genetics principle describing the frequency of genes in a population.

What is Quantitative Genetics?

The branch focusing on continuous traits; includes marker-assisted selection, transgenic animals, and gene mapping.

What is an EPD?

Expected Progeny Difference; a calculated performance measure for within-breed comparisons.

What is Heritability (h2)?

A measure of the strength of the relationship between breeding values and phenotypic values; high h2 means phenotype is a good indicator.

What is a Polygenic Trait?

A trait affected by many genes; no single gene has overriding influence.

What is a Simply-Inherited Trait?

A trait affected by only a few genes (e.g., horned vs. polled).

What is a Qualitative Trait?

A categorical trait that cannot be measured (e.g., color, horn status).

What is a Quantitative Trait?

A trait that can be measured and shows continuous expression (e.g., birth weight, average daily gain).

What is Domestication?

Artificial selection for human needs (food, work, clothing, companionship, etc.); most farm animals were domesticated about 5,000–10,000 years ago.