501 Animal Breeding And Genetics Study Guide

Front 1

the genetic makeup of an animal which is greatly affected by environmental interactions.

Back 1

genotype

Front 2

physical characteristics and performance of an animal

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phenotype

Front 3

physical conformation of an animal.

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type

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the Austrian monk ___ performed his now famous breeding experiments with peas and published his results in 1866

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Gregor Mendel

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Mendel's ___ are the basis of all genetic and animal-breeding theory practiced since his time

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Laws of Inheritance

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rod-shaped bodies that occur in pairs in the nuclei of cells and that carry the genetic makeup of the animal in the form of genes arranged along the chromosome

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chromosomes

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hereditary units located on a chromosome; composed of DNA

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genes

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location on a chromosome where a particular gene is found

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locus

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cell division of somatic or body cells. Produces identical diploid daughter cells (half from each parent)

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mitosis

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having two sets of homologous chromosomes. Symbolized by 2n

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diploid

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cell division that produces gametes, which contain the haploid number of chromosomes

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meiosis

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# of chromosomes found in the gametes, which is half the normal number of chromosomes found in the somatic cells

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haploid

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cell formed by the union of a sperm and an ovum

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zygote

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alternative form of a gene found on the same location of the homologous chromosome

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allele

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both genes at a particular location are the same allele

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homozygous

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where two alleles at a particular location are not the same

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heterozygous

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gene whose effect masks the phenotypic expression of its allele

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dominant

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gene whose expression is hidden by a dominant gene

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recessive

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the likelihood that some event or outcome will occur

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probability

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causes periodic episodes of muscle tremors ranging from shaking to to complete collapse in horses.

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Hyperkalemic Periodic Paralysis
(HYPP)

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primarily determined by additive genes

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polygenic traits

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phenotypic expression of some genes are limited to one sex

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sex limited genes

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all chromosomes excluding the X and Y

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autosomes

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genes that are carried on the nonhomologous portion of the X chromosome (usually recessive)

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sex-linked

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genes carried on the portion of the Y chromosome that has no homologous portion on the X chromosome. Passed only from father to son.

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Holandric Inheritance

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chemical change in the gene such that it functions differently than before the change; passed on to posterity

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mutation

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only ___ of the genes from each great-grandparent is passed on to an animal

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one-eighth

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4 basic systems of breeding

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inbreeding, crossbreeding, linebreeding, and outcrossing

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breeding of animals more closely related than the average relationship in the population. Decrease in performance of traits.

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inbreeding

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breeding an animal to a common ancestor; not as closely related as inbreeding

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linebreeding

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system of mating animals less closely related than the average for the breed. Opposite of inbreeding and increases heterozygosity.

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outcrossing or outbreeding

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mating of animals of different breeds. Increases hybrid vigor but only lasts one generation.

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crossbreeding

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animal with 2 purebred parents that is hence eligible for inclusion in the breed registry

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purebred

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animal whose name is recorded in the breed registry.

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registered

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animal that possesses the distinct characteristics of a particular breed but at least one of its parents cannot be traced to the registry

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grade

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refers to the first generation progeny following the parental or P1 generation

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F1

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2 dimensional grid used to determine the possible zygotes obtained from a mating

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Punnet Square

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sex cell

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gamete

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the removal from a herd of animals w. lower genetic or phenotypic value is called ___

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culling

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an animal's offspring

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progeny

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aka hybrid vigor

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heterozygosity

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means hornless

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polled