BIOL1020 Lecture Notes - Lecture 9: Gregor Mendel, Reciprocal Cross, Zygosity
Document Summary
Gregor mendel: father of genetics: pea plants have several characters that can take two forms, seed colour, seed shape, flower colour, flower position, stem length, pod colour, pod shape, mendel looked at how they were inherited. Mendel"s methods: p- parents from two pure breeding lines are crossed, f1- first filial generation, phenotype scored, then self-fertilized, f2- second generation, phenotype scored, also made test crosses , f1 x p. Monohybrid (single trait) crosses: mendel noticed, one trait lost in f1, reappeared in f2, 3:1 ratio in f2, reciprocal cross have similar results, mendel concluded: Inheritance is particulate: 2 copies of heritable factor, one trait is dominant. Mendel"s principles: dominance: phenotypes depends on inheritance of dominantn and recessive alleles, segregation (mendel"s first pricniple): the two alllels separate from each other into gametes. Independent assortment (mendel"s second principle): genes segregate independently when gametes are formed: mendelian genetics works in all eukaryotes.
