intro to genetics

genetics

• biology of heredity and variation, deals with the wayin which traits are passed on or transmitted to their offspring.

• Study of genes, genetic variation and heredity in living

breeding

concerned with the proper selection and use of traitsof the parents to produce offspring with predictable and desirabletraits for the improvement of animals.

genes

functional unit of inheritance consisting mostly of DNA

DNA

a complex molecule that forms the genetic code for allliving things

chromosomes

long strands of DNA and associated proteinspresent in the nucleus of every cell of an organism; comes inpairs, one from the dam, one from sire.

animal breeding

branch of animal science thatdeals with the evaluation of the genetic valueof livestock.

line

a group of animals descended from orrelated to a specific animal or source ofgenetic stock.

strain

a group of animals within a breedwith traits that distinguish them from othersin the breed.

alleles

different forms of a segment of DNA that can exist at aparticular site of the chromosome.

locus

particular site of a gene in a chromosome

phenotype

appearance of an organism; visible or measurableproperties.

genotype

genetic factors responsible for creating the phenotype,underlying genetic constitution of a phenotype; combination of genesat a single locus or at a number of loci.

homozygous genotype

is a one-locus genotype containingfunctionally identical genes.

heterozygous genotype

a one-locus genotype containingfunctionally different genes

abortion

expulsion of dead fetus before the end ofgestation period

premature birth

expulsion of live fetus before the end ofgestation period

stillbirth

expulsion of dead fetus at the end of gestationperiod

fertility

ability of the animal to produce viable offsprings

barrenness

reproductive failure in animal

prolificacy

ability of the animal to produce large numberof ofsprings

fecundity

ability of the animal to produce large number of sperm or ova

potency

ability of the male animal to perform copulation

conception rate

the number of pregnant female to the number of bred female in the herd

dystocia

dificult parturition

age of puberty

sexual maturity

heat or estrus period

desire of female animal to be mated.

heat or estrus cycle

Onset of first heat up to next heat period.

ovulation

shedding of ova from ovary.

copulation

act of mating

fertilization

union of sperm and ova to form a zygote

nidation

implantation of zygote in the horn of the uterus.

gestation

act of pregnancy

parturition

act of delivery

lactation

act of nursing the newborn animal

weaning

act of separating the young from the dam or mother.