sex chromosome - an X or Y chromosome, which determines the genetic sex of an organism autosome a chromosome that is not involved in determining the sex of an organism
homologous chromosome - a chromosome that contains the same sequence of genes as another chromosome
gene - a part of a chromosome that governs the expression of a trait and is passed on to offspring; it has a specific DNA sequence
allele - a different form of the same gene
karyotype - a photograph of pairs of homologous chromosomes in a cell
spermatogenesis - the process of producing male gametes (sperm) in mammals
oogenesis - the process of producing female gametes (eggs) in mammals
crossing over - the exchange of chromosomal segments between a pair of homologous chromosomes
non-disjunction - the failure of homologous chromosome pairs or sister chromatids to separate during meiosis
monosomy - the loss of a chromosome as a result of nondisjunction
trisomy - the gain of an extra chromosome as a result of nondisjunction
selective breeding - the process of breeding plants and animals for desirable traits
artificial insemination - the process by which sperm are collected and concentrated before being introduced into the female’s reproductive system
embryos transfer - the process by which an egg that has been fertilized artificially is transferred into a recipient female’s uterus.
in vitro fertilization - the technique used to fertilize egg cells outside the female’s body
cloning - a process that produces identical copies of genes, cells, or organisms
gene cloning - the use of DNA manipulation techniques to produce multiple copies of a single gene or segment of DNA
recombinant DNA - a molecule of DNA that includes genetic material from different sources
stem cell - an undifferentiated cell that can develop and become specialized into different cell types of the body
therapeutic cloning - the process of replacing an egg cell’s nucleus with the nucleus from a somatic donor cell to produce a cell line of genetically identical cells
reproductive cloning - the process of producing genetically identical organisms