Question

Mendelian ratios are modified in crosses involving autotetraploids. Assume that one plant expresses the dominant trait green seeds and is homozygous (WWWW). This plant is crossed to one with white seeds that is also homozygous (wwww).
If only one dominant allele is sufficient to produce green seeds, predict the F1 phenotypic ratio of such a cross. Assume that synapsis between chromosome pairs is random during meiosis.
A. 1 green : 3 white
B. All white
C. All green
D. 1 green : 1 white

Answer 1

Answer:

C All green

Explanation:

This cross involves four genes that are the same i.e. code for the same trait. According to the question, the green allele (W) is dominant over the white allele (w). This cross will follow the Mendel's law of dominance, that one allele is capable of masking the expression of another allele I a heterozygous state.

Hence, this WWWW and WWWW parent will produce WW and ww gametes respectively, which when used in a punnet square will result in an all green F1 phenotypic offsprings i.e. WWww.