Question

Michael Lynch and his colleagues demonstrated in yeast that mutations occur rarely-in fact a single yeast cell may not experience a single point mutation in its genome. How can we reconcile the low rate of mutation with the fact that mutation is the engine that drives evolution?

Answer 1

Michael Lynch is an evolutionary geneticist ,he arugues that much of the diversity of genetics in eukaryotes arose not beacause of natural selection but due to genetic machineray that cleans up mutations do not work properly in small populations to keep them out,he showed mutation rate is higher for multicellular organisms comparitive to the organisms such as yeast and invertebrates.

Mutation is the permanent alteration of nucleotide sequence of genome of an organism,they are necessary for genetic variation,they create genetic diversity by introducing new alleles in to the population ,allele is an alternative expression of a gene.Genetic is important in the survival and adaptability of a species when a population habitat changes, they have to adapt to survive in the changing environment ,it will determine their ability to cope with an environmental challenge.

There are different types of mutations, A single mutation will have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations with some effects. Mutational effects can be beneficial or harmful, or neutral, depending on their context or location.

Phenotypic evolution occurs mainly by mutation of genes that interact with one another in the developmental proces,it occurs among different phyla or classes of organisms is a product of accumulation of mutations and their conservation that have facilitated adaptation to different environments.

Mutation rate is frequency of new mutations in a single gene or organism over a various amount of time, By natural selection, unfavorable mutations will be eliminated from a population while favorable changes are generally kept for the next generation.Mutation rate differs with in the organisms and regions, higher mutation rates increase the rate of beneficial mutations, too low leads to the species that are not adaptive,too high leads to the diseased and decreased fitness, the evolution may prevent the lowering of the mutation rate in order to maintain optimal rates of adaptation.