Question

How does transgenerational epigenetic inheritance affect Darwinian selection? Emphasise on how epigenetics affects natural selection and give examples

Answer 1

Transgenerational epigenetic inheritance is the vertical transmission of epigenetic markers from parents to the offsprings. This affects the phenotype in the offsprings whreas the primary structure of DNA remains un alterd.

The epigenetics indirectly affects natural selection explained by Darwin by affecting the genotypes. The highlighted thing is that it is not essential for the epigenetically-inherited phenotype to become fixed into the genotype to affect the evolution of traits.The major question askes was that whether epigenetically-developed traits themselves can actually added to the genome permanently? or whether having the markers that generate them have indirect influence on the subsequent genome through evolutionary process like natural selection or other mechanisms. Studies on one kind of DNA methylation at mutational hotspots, like CpG islands have considerable importance at this point. The methylated cytosine or 5-methyl cytosine can undergo spontaneous deamination to thymine, whereas methylated guanine converts to uracil in CpG islands. These mutations, are not at all considered as DNA damage, and are not subjected to any kind of repair by DNA repair mechanisms. Consequently, these mutations become fixed in the genome and may affect the process of speciation