NEET BIOLOGY

Detailed explanation-1: -The expected genotype ratio when two heterozygotes are crossed is 1 (homozygous dominant) : 2 (heterozygous) : 1 (homozygous recessive). When a phenotypic ratio of 2 : 1 is observed, there is probably a lethal allele.

Detailed explanation-2: -If both parents are heterozygous (Ww), there is a 75% chance that any one of their offspring will have a widow’s peak (see figure). A Punnett square can be used to determine all possible genotypic combinations in the parents. A pedigree that depicts a dominantly inherited trait has a few key distinctions.

Detailed explanation-3: -When two heterozygous plants are crossed, the resulting progeny mostly show the dominant phenotype. But, the recessive phenotype reappears.

Detailed explanation-4: -If heterozygous parents are being crossed, there is a possibility of having both, dominant and recessive, traits appearing in F1 generation. Each heterozygous parent will produce two types of gametes, one with dominant and one with a recessive allele. When these gametes fuse, they give rise to all three combinations.