2.+Organisms+inherit+genetic+information+in+a+variety+of+ways

MAJOR UNDERSTANDINGS 2.1a Hereditary information is contained in genes. Genes are composed of DNA that makes up the chromosomes of cells. 2.1b Each gene carries a single unit of information. A single inherited trait of an individual can be determined by one pair or by many pairs of genes. A human cell contains thousands of different genes. 2.1c Each human cell contains a copy of all the genes needed to produce a human being. 2.1d In asexual reproduction, all the genes come from a single parent. Asexually produced offspring are genetically identical to the parent. 2.1e In sexual reproduction typically half of the genes come from each parent. Sexually produced offspring are not identical to either parent. 2.2a In all organisms, genetic traits are passed on from generation to generation. 2.2b Some genes are dominant and some are recessive. Some traits are inherited by mechanisms other than dominance and recessiveness. 2.2c The probability of traits being expressed can be determined using models of genetic inheritance. Some models of prediction are pedigree charts and Punnett squares.