In tomato plants, purple leaf color is controlled by a d...

Question

In tomato plants, purple leaf color is controlled by a dominant allele A, and green leaf by a recessive allele a. At another locus, hairy leaf H is dominant to hairless leaf h. The genes for leaf color and leaf texture are separated by 16 m.u. on chromosome 5. On chromosome 4, a gene controlling leaf shape has two alleles: a dominant allele C that produces cut-leaf shape and a recessive allele c that produces potato-shaped leaf.

The cross of a purple, hairy, cut plant heterozygous at each gene to a green, hairless, potato plant produces the following progeny:

Phenotype Frequency % _
Purple, hairy, cut 21
Purple, hairy, potato 21
Green, hairless, cut 21
Green, hairless, potato 21
Purple, hairless, cut 4
Purple, hairless, potato. 4
Green, hairy, cut 4
Green, hairy, potato. 4 _
100
Give the genotypes of parental and progeny plants in this experiment.

Accepted Answer

Hey, everyone. Let's take a look at this question together. If we cross true breeding organisms, the F two progeny will produce a phenotypic ratio of 9 to 3 to 3 to 1. The following genotypes contribute to the most dominant phenotypic trait in the F two progeny. Except which is it answer choice. A homozygous dominant for X, heterozygous for Y, answer choice. B heterozygous for X, heterozygous for Y answer choice. C homozygous recessive, X and homozygous dominant, Y or answer choice. D heterozygous X and Homozygous dominant. Y, let's work this problem out together to try to figure out which of the following genotypes does not contribute to the most dominant phenotypic trait in the F two progeny. So we can recall that the dominant, you know, type of the two traits contributes the most abundant proportion, meaning that the genotypes that have either one or two dominant alleles for each trait contributes the most abundant proportion. And so these are your genotypes where you have homozygous dominant, X and Homozygous dominant, Y, heterozygous X and Homozygous dominant, Y, homozygous dominant, X, but heterozygous Y and lastly, you have heterozygous, X and heterozygous Y. And so these are the dominant phenotypes or the two traits that contributes to the most abundant proportion. And so looking at our answer choices, we can see that answer choice. A B and D all have at least one X and one Y being dominant. And then looking at answer choice C, we could see that we do not have a dominant allele for X since we have homozygous recessive for X, which means that it is not giving the most dominant phenotype. And so answer choice C homozygous recessive X and homozygous dominant Y is the correct answer because of the following genotypes that contribute to the most dominant phenotypic trait in the F two progeny. Answer choice C is the only genotype here without a dominant X allele. So it does not contribute to the most dominant phenotypic trait. So answer choice C is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

Key Concepts

Mendelian Genetics

Gene Linkage and Recombination

Phenotypic Ratios

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