Biology 1001A Lecture Notes - Lecture 10: Enzyme, Scientific Modelling, Probability Distribution
Document Summary
Bio 1001a - lecture 10 inheritance of variation. We inherit around 80 new mutations from your parents that they never had. Alternate allele have different dna sequences: ex. Variation means differences in double-stranded dna sequence. Origin is inherent in chemistry of dna, enzymology of replication/repair/recombination/cytoskeleton. Can be influenced by physical, chemical, biological agents/conditions. Origin is undirected with respect to survival value: cells can"t call for specific mutation for better fitness. Origin is not randomly distributed around genome. Only germ-line variation is subject to selection. People used to believe that inheritance was by blending . In reality, polygenic traits show continuous variation in population: looks like blending, but the trait is controlled by many genes. Mendel, through careful experimentation with controlled crosses and quantitative analyses, came up with scientific model. Alleles of two genes assort independently in dihybrid crosses: results in classic 9:3:3:1 ratio in f2 progeny.
