BIOL 205 Lecture Notes - Chlorophyll, Centromere, Chloroplast
27 Sep 2013
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If two genes are on different chromosomes, the gene pairs are separated by semicolon a/a; If they are on the same choromosome, the alleles on one homolog are written adjacently with no punctuation and are separated from those on the other homolog by a slash ab/ab or. How many distinct genotypes does a cross produce. A heterozygote for a single gene (a/a) is a monohybrid. A double heterozygote such as a/a . B/b is a dihybrid and by studying dihybrid crosses, Mendel came up with his second principle of heredity. 9:3:3:1 ratio for dihybrid cross is a consistent ratio in dihybrid f2 phenotypic ratio. The proportions of the 4 possible outcomes could be calculated using the product rule to multiply along the branches in the diagram: ex. Of f2 is round, and of round seeds will be yellow so x = 9/16 of peas are round and yellow.
