Haplotype convergence is the unrelated appearance of identical

haplotype A haplotype ( haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA or ...

s in separate populations, through either

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

or random chance.

Description

Haplotype convergence is rare, due to the sheer odds involved of two unrelated individuals independently evolving exactly the same genetic sequence in the site of interest. Thus, haplotypes are shared mainly between very closely related individuals, as the genetic information in two related individuals will be much more similar than between unrelated individuals. Substitution bias further increases the likelihood of haplotype convergence, as this increases the probability of mutations occurring at the same site. Sequences may also diverge from the same original sequence and then revert, converging in this manner. Convergence through convergent evolution in two unrelated groups is much less common, as derived traits may arise through dramatically different pathways. Erroneously determining two individuals do be identical due to haplotype convergence becomes much less likely when more genetic markers are tested, since that would require a larger amount of extremely rare coincidences. With modern high-throughput sequencing approaches, sequencing a large set of markers, or even the entire genome, is much more feasible and greatly minimizes these issues.

Examples

In some regions, due to low diversity in the Y-STR gene (often used to study surname origin), haplotype convergence may confuse analyses, concluding unrelated individuals to be very closely related. Similarly, a study of New World

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

haplogroups observed that similarities in haplotypes between Native Americans and Asians were a result of the hypervariability of the HVSI region in mitochondrial DNA, rather than common ancestry. As an example of haplotype convergence due to convergent evolution in more distantly related groups,

threespine stickleback The three-spined stickleback (''Gasterosteus aculeatus'') is a fish native to most inland and coastal waters north of 30°N. It has long been a subject of scientific study for many reasons. It shows great morphological variation throughout its ra ...

in blackwater environments similar to that of the ancient bluefin killifish and

black bream Black bream may refer to one of several fish species: * Black drummer, ''Girella elevata'' * Black seabream, ''Spondyliosoma cantharus'', a silvery fish found in northern Europe and the Mediterranean * Galjoen, ''Dichistius capensis'', the nationa ...

independently evolved the same haplotype in the SWS2 gene, which promotes better eyesight in those conditions.

References

{{DEFAULTSORT:Haplotype convergence Evolutionary biology Genetic genealogy