Question

Which of the given traits of pea plants selected by Mendel expresses itself only in homozygous conditions? Terminal flower, green seed, yellow pod, constricted pod, violet petals, dwarf stem.

Answer 1

Mendel's Law of Dominance:

1. Individuals are considered to be homozygous for a characteristic if the two alleles that make up the pair are the same, and heterozygous for the trait if the two genes are different.
2. Based on his studies on pea plants, Mendel proposed that single genes regulate all traits.
3. When discussing Mendel's experiments on inheritance, his Law of Dominance comes into play. In the presence of dominant alleles, dominant alleles are constantly expressed, whereas recessive alleles are silenced.
4. There are two alleles for each gene in diploid cells, under the following conditions —
   1. Both alleles have a high level of dominance (homozygous condition) TT is an example.
   2. Both alleles have a recessive inheritance pattern - ttthe shape.
   3. One allele is dominant, whereas the other is recessive - Tt (heterozygous).
5. The dominant phenotype is expressed in heterozygous conditions (Law of Dominance), whereas recessive alleles are expressed in phenotypes only in homozygous conditions.
6. During his experiment, Mendel investigated seven unique qualities, each with two distinct, discontinuous features.
7. Only the violet petals trait is dominant among the six qualities given in the question; the others are recessive.
8. The homozygous condition is required for these recessive features to be expressed.
   

Trait	Dominant allele	Recessive allele
Color of the seed	Yellow	green
Height of stem of plant	Tall	dwarf
Color of the pod	Green	yellow
Shape of the seed	Round	wrinkled
Shape of pod	Inflated	Constricted
Position of the flower	Axial	Terminal
Color of the flower	Violet	White