GENE 3200 Lecture Notes - Lecture 2: Gamete, Meiosis, Chromosome
Document Summary
Two locus cross revisited: purple/red flower color (p locus, long/round pollen grain shape (l locus, each locus is a good mendelian locus. Excess of double dominant and double recessive phenotypes = coupling phenotypes. Independent assortment: freq (parentals) = freq (recombinants: frequency of parentals equals frequency of recombinants, linkage: freq (parentals) > freq (recombinants, therefore, 0 freq(recombinants) 1/2. Recombinant is due to physical breaking of chromosomes and religation using knobs and tails. Two categories that are most abundant are always the parentals. Aabb x aabb: a and b are on different chromosomes which means you should see independent assortment. Thus, the map distance is 50cm: rab if a and b are on same chromosomes = 50cm, 50% recombination frequency because only a certain of linkage can be detected. If loci are close on the same chromosome, we can detect this. 50% is the max recombination frequency we can expect because parental gametes are always higher than recombinant gametes.
