Mutation bias

The concept of mutation bias appears in several scientific contexts, most commonly in molecular studies of evolution, where mutation biases may be invoked to account for such phenomena as systematic differences in codon usage or genome composition between species.

Evidence for an evolutionary impact of mutation biases on changes involved in adaptation is summarized in the Arrival Bias article (note that [6] argued in 2019 that this line of argument is flawed and that apparently mutation-biased patterns of change are better explained by selection).

In the past, due to the technical difficulty of detecting rare mutations, most attempts to characterize the mutation spectrum were based on reporter gene systems, or based on patterns of presumptively neutral change in pseudogenes.

More recently, there has been an effort to use the MA (mutation accumulation) method and high-throughput sequencing (e.g.,[7] ).

In a variety of organisms, transition mutations occur several-fold more frequently than expected under uniformity.

[9] The bias in animal viruses is sometimes much more extreme, e.g., 31 of 34 nucleotide mutations in a recent study in HIV were transitions.

[10] As noted above, the bias toward transitions is weak in yeast, and appear to be absent in the grasshopper Podisma pedestris.

Haldane found that in hemophilia, the blood clotting disorder originated on the X chromosomes is due to fathers' germline mutation.

[17] By using the equation, we could estimate the ratio of male to female mutation rates α ≈ 6.

In some organisms with a shorter generation time than humans, the mutation rate in males is also larger than those in females.

The ratio of the number of germ cell divisions from one generation to the next in males to females is less than that in human.

[22][23] Contrary to humans, bird males are homogametes (WW), and females are heterogametes (WZ).

A mutation is a heritable variation in the genetic information of a short region of DNA sequences.

[27] These C-to-T nucleotide substitutions occur 10-50 times faster than that at rest sites in DNA sequences, especially likely appeared in the male and female germlines.

[32] Starting in the 1990s, it became clear that GC-biased gene conversion was a major factor—previously unanticipated—in affecting GC content in diploid organisms such as mammals.

[2] Mutation biases are not constant, but vary taxonomically, as shown in the table below from,[39] and by conditions such as nutritional state.