Basic genetics. Haixu Tang School of Informatics. Mendel’s two innovations . Developed pure lines a population that breeds true for a particular trait Counted his results and kept statistical notes . Phenotypes of Mendel's pea plants. round or wrinkled seed phenotype
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Thus the F2 is genotypically 1/4 Dd : 1/2 Dd : 1/4 dd
Backcross One or (BC1) Phenotypes: 1 Tall : 1 Dwarf
BC1 Genotypes: 1 Dd : 1 dd
We have followed the expression of only one gene. Mendel also performed crosses in which he followed the segregation of two genes. These experiments formed the basis of his discovery of his second law, the law of independent assortment.
Degrees of freedom (df) = n-1, where n is the number of classes
Let's test the following data to determine if it fits a 9:3:3:1 ratio.
Number of classes (n) = 4
df = n-1 + 4-1 = 3
Chi-square value = 0.47