Mendelian Genetics Questions and Answers

Following are the important Mendelian genetics questions and answers. Students can prepare these test questions to prepare for their exams.

1. What is Clinical genetics?

Ans: It includes the training of genetists to diagnose, treat and counsel patients with genetic disorders or syndromes.

2. Who did discover Mendel’s work?

Ans: Mendel’s work was discovered by three European scientists, Hugo de Vries, Carl Correns and Erich von Tschermak.

3. What was the contribution of Thomas Hunt Morgan in genetics?

Ans: He and his assistants later integrated the theoretical model of Mendel with the chromosome theory of inheritance. He proved the chromosomes of cells hold the actual hereditary particles. They created classical genetics. It finally proved Mendel’s work. Mendelian genetics questions and answers

4. What is genomics?

Ans: A more recent development is the rise of genomics. It attempts the study of large-scale genetic patterns across the genome for a given species. Genomics depends on the availability of whole genome sequences and computer tools for analysis of large set of data.

5. What is genetic conservation?

Ans: Genetic conservation is a science that aims to apply genetic methods to deal with the maintenance, loss, and restoration of biodiversity.

6. What is the Role of International organization in genetic conservation?

Ans: United Nations action programs, with the International Biological Program (IBM), in collaboration with FAQ, playing a major part. A global network of genetic resources centers was endorsed by the United Nation as Conference on the Human Environment.

7. Give two reasons for use of pea as experimental plant by Mendel?

Ans: It is easy to cultivate and it grow well in his garden. Its flowers are hermaphrodite.

8. What are true breeding verities? Give example?

Ans: A variety which always produces offspring identical to the parents by self-fertilization is called true breeding variety. For example, a true breeding wrinkled seed plant produced only wrinkled seeds.

9. What is meant by contrasting pair of trait?

Ans: Each trait had two clear cut alternative forms or varieties e.g., seed shape has a round or wrinkled phenotype, plant height is either tall or short, seed color is yellow or green. Mendel called them contrasting pair of trait. He focused on seven such pairs. Mendelian genetics questions and answers

10. Name seven Mendelian characters of pea?

Ans: Tall/dwarf, round/wrinkle seed, purple/white flower, yellow green seed, axial/terminal flower, constricted/inflated pod and green/yellow pod color.

11. Differentiate between monohybrids and dihybrids?

Ans: The offspring in one character are called monohybrids. The offspring produced by the cross fertilization between two plants, differing in two characters are called dihybrids.

12. Differentiate between monohybrid and dihybrid crosses?

Ans: The cross in which one trait is followed at a time is called monohybrid cross. The cross in which two traits is followed at a time is called dihybrid cross. Mendelian genetics questions and answers

13. What is parental generation?

Ans: When two pure line parents are crossed with each other, they are called first parental generation (P₁).

14. What is first filial generation?

Ans: The offspring of the P₁ generation are called F₁ or first filial generation. All F₁ offspring were round like one of the parents.

15. What are dominant and recessive alleles?

Ans: The trait that appears in F₁ is called dominant trait or allele. The trait which is masked in F₁ is called recessive trait or allele.

16. Define law of segregation?

Ans: According to law of segregation, the two coexisting alleles for each trait in an individual segregate from each other during meiosis. So that each gamete receives only one of the two alleles. Alleles unite again at random fertilization of gametes when zygote in formed. Mendelian genetics questions and answers

17. Differentiate between homozygous and heterozygous alleles?

Ans: When both the alleles of a gene pair in an organism are same, it is called homozygous. When both the alleles of a gene pair in an organism are different, it is called heterozygous.

18. What is test cross?

Ans: The cross which is used to determine the genotype of an individual is called test cross. An individual showing a dominant phenotype is crossed with an individual its recessive phenotype.

19. What were the result of Punnet square for law of segregation?

Ans: Punnett square indicates that 1/4 of F₂ progeny have ‘RR’ (homozygous round), _{1/4 + 1/4 = 1/2} Rr (heterozygous round), and _1/4 rr (wrinkled).

20. What are the genotypic and phenotypic ratios of law of segregation in F₂?

Ans: Mendel actually observed 3:1 phenotypic ratio in F_2. While its genotypic ratio 1:2:1 genotypic in F₂.

21. What are the particulate hereditary factors of Mendel?

Ans: Mendel proposed that each contrasting form of a trait was determined by particulate hereditary factors. He called these hereditary factors as “elementen” (allele). Mendelian genetics questions and answers

22. What is linkage of genes?

Ans: The genes are present on the same chromosomes are called linked genes. So, all the genes present on the homologous chromosomes are linked.

23. What are linkage groups?

Ans: Thus, genes present on the homologous chromosomes are linked genes and they form linkage groups.

24. Can linked gene assort independently?

Ans: Independent assortment of genes depends on the independent assortment of their chromosomes. Thus, genes present on the homologous chromosomes are linked genes and they form linkage groups. The linked genes cannot assort independently.

25. Why Mendel did not face the problem of linkage?

Ans: Pea has seven homologous pairs of chromosomes. Mendel was lucky that he studied those seven traits whose allelic pairs were present on different homologous chromosomes. So, they were not linked.

26. What is dominance relationship? Name different dominance relations?

Ans: Dominance is a physiological effect of an allele over its partner allele on the same gene locus. Different dominance relations are complete dominance, incomplete dominance, Codominance and over dominance.

27. What is complete dominance?

Ans: In this case, one allele (R) is completely dominant over the other (r) and the presence of the recessive allele is functionally hidden.

28. What is incomplete dominance? Give examples?

Ans: When the phenotype of the heterozygote is intermediate between the phenotypes the two homozygotes. it is called incomplete or partial dominance. Its example is flower color in 4 O’ clock.

27. Does incomplete dominance follow the law of segregation?

Ans: There is blending of flower colors in F₁. So it seems to be against the law of segregation of Mendel. But red and white flowers reappear in F₂. It indicates that blending does not occur at genetic level. The 1:2:1 ratio in F₂ shows that the law of segregation is valid for incomplete dominance.