IMED2004 Lecture Notes - Lecture 25: Gene Mapping, Gamete, Allele
26 Mar 2020
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Mendel"s first law- segregation of alleles: cells contain 2 copies (alleles of each gene, alleles separate during gamete formation (meiosis, gametes carry only one copy of each gene (random, single-gene inheritance model explains mendel"s ratios: Experiments: (remember- a monohybrid is a heterozygote for a single gene e. g. a/a: dihybrid: double heterozygote (e. g. a/a, b/b) If the genes are on different chromosomes: a/a, b/b. If the genes are on the same chromosome: ab/ab. If the location of the 2 genes is not known: a/a + b/b. Dihybrid crosses- the explanation: the number of individuals for each trait, seed shape: All 3:1: the 9:3:3:1 ratio is made up of 2 different 3:1 ratios combined at random. Linked genes travel together in meiosis, arriving at the same destination (i. e. same gamete) and are not expected to assort independently: all characteristics examined by mendel in peas did.
