BIO 325 Lecture Notes - Heterokaryon, Mitosis, Single-Nucleotide Polymorphism
29 Sep 2013
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Three point mapping - the parent must be heterozygous for all three genes under consideration. Dcos doesn"t happen frequently -- numbers are lower than expected. Noncrossover f2 phenotypes - occur in the greatest proportion of offspring. Double-crossover phenotypes - occur in the smallest proportion. Reciprocal classes - f2 phenotypes complement each other. The distance between two genes in a three-point cross is equal to the percentage of all detectable exchanges occurring between them and includes all single and double crossovers! Sco = pr - v = 22. 3% = 22. 3% 22. 3 map units. Sco = pr - bm = 43. 4% = 43. 4% 43. 4 map units. Expected dco = 0. 223 x 0. 434 = 0. 0968 ---> 9. 7% *this phenomenon shows interference (i) = 1 - c. *since this is less than 1 and positive, then that means the crossover is positive interference - Oppositely, negative interference means that one crossover event increases the frequencies of other crossovers.
