Question

In humans, right-handedness is dominant over left-handedness. What offspring would be expected from left-handed parents?
(a) Only left-handed
(b) Only right-handed
(c) Left-handed and right-handed tooth
(d) Neither left-handed nor right-handed

Answer 1

Take right-handedness as dominant R and left-handedness as r being recessive. Since the parents are left-handed, they are homozygous recessive genotypes (rr). By drawing a Punnett square one can get the genotype of the offspring.

Complete answer:
The homozygous recessive genotype of the parents is crossed and a Punnett square is made to determine the genotype of the offspring.

| r| r
---|---|---
r| rr| rr
r| rr| rr

Since, the crossing of the gamete results in the recessive trait rr (left-handedness), the offspring will be only left-handed.

Additional Information: - For a certain genetic variant, a monohybrid cross is the fusion of two individuals with homozygous genotypes that result in the opposite phenotype.
- Each allele separates at the moment of gamete formation during meiosis. There are no mixing and various gametes are transferred to characters. Only one form of gametes is produced by homozygotes and different forms of gametes are produced by heterozygotes.
- After conducting experiments on pea plants for seven years, Gregor Mendel suggested the rule of inheritance.
-The laws of inheritance of the Mendel include supremacy law, segregation law, and separate assortment law.
-The segregation law states that every individual has two alleles and that only one allele is passed on to the offspring.
-The law of separate assortment states that one pair of genes is separate from another pair's inheritance.
So, the answer is, “Only left-handed.”

Note: - The genetic structure is known as the genotype. On the opposite, a phenotype is known as physical appearance.
-In pairs known as alleles, the genes are passed from parents to offspring.
-During gametogenesis, there is a 50 percent risk of one of the two alleles fusing with the other parent when the chromosomes are halved.
-They are known as homozygous alleles when the alleles are the same, and they are known as heterozygous alleles when the alleles are different.