Question

Which of the following describes “genome shock” as hypothesized by Barbara McClintock?

            A) shocking DNA with electric currents increases the rate of mutations in the genome

            B) rapid transposition of genetic elements leads to high frequency of new mutations

            C) genome shock is detrimental to a species as it leads to extinction over many generations

            D) genome shock limits the rate of transposition of genetic elements

How does the structure of the human genome minimize the impact of mutations?

Answer 1

Ans. (d) genome shock limits the fate of transposition of genetic elements.

Explanation: Genetic shock involves reorganization and changes in the genome to cope with the effects including X-rays, duplication of chromosomes etc. Transposition of genetic elements is the movement of gmobile genetic elements and hence it leads to reorganization of genome. Hence, the phenomenon of genetic shock limits the effect of transposition of genetic elements.

- Human genome consists of linear double stranded DNA in the form of chromosomes. There is presence of allele i.e. alternate form of genes, on the homologous chromosome pair at same loci. This reduces the expression of mutation at one allele since a trait is controlled by two alleles. There is mechanism in human genome to correct errors in genome during replication and transcription process. This reduces the mutations.