Question

Dominant gene for tallness is T and for yellow is Y. A plant heterozygous dwarf and green offspring would be
A. 1/4
B. 4/16
C. 3/16
D. 1/16

Answer 1

Hint: Each individual receives two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed, it is known as the dominant gene whereas the effect of the other allele is masked, is known as the recessive gene.

Complete answer:
The key concept in Mendelian inheritance and classical genetics is Dominance.
Letters and Punnett squares are employed to demonstrate the principles of dominance in teaching. The use of upper case letters for dominant alleles and lower case letters for recessive alleles is a widely followed convention. A classic example of dominance is the inheritance of seed shape in peas. Peas may be round, linked with allele R, or wrinkled, linked with allele r. In this case, three combinations of alleles (genotypes) are seen: RR, Rr, and rr. The RR (homozygous) individuals possess round peas, and the rr (homozygous) individuals have wrinkled peas. In Rr (heterozygous) individuals, the R allele masks the presence of the r allele, so these individuals also possess round peas. Thus, allele R is dominant over allele r, and allele r is recessive to allele R.

In this question-
A cross is made between a plant that is tall and has yellow seeds (TTYY) with another plant that is dwarf and has green (ttyy) seeds. In the F1 generation, progeny with tall and yellow seeds (TtYy) is obtained. When this is selfed, in the F2 generation, 9 progeny with tall yellow seeds 3 progeny with tall wrinkled, 3 progeny with dwarf yellow seeds 1 progeny with dwarf green seeds are established. Genotypically, 2 progeny will be showing parental genotypes (TTYY, ttyy).

So, the correct option is D- ‘1/16'.

Note: Freckles, cleft chin, and dimples are all crucial examples of a dominant trait. Having almond-shaped eyes is a dominant trait whereas having round eyes is a feature regulated by recessive alleles. The trait of detached earlobes, contradicted to attached earlobes, is dominant. Right-handedness is dominant over left-handedness.