Domestication islands refers to regions within DNA that do not change despite gene flow between wild and domesticated species.

Speciation islands

In 2005, a study of

genomic DNA Genomic deoxyribonucleic acid (abbreviated as gDNA) is chromosomal DNA, in contrast to extra-chromosomal DNAs like plasmids. Most organisms have the same genomic DNA in every cell; however, only certain genes are active in each cell to allow for c ...

within species of mosquitoes found that there were "speciation islands" of genes that remain differentiated despite considerable gene flow, and are therefore expected to contain the genes responsible for reproductive isolation between species. In the following years, there was criticism of this proposal and that there might be other explanations, including

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...

diversity within species or reduced diversity. This debate continues.

Domestication islands

In 2007, a study of the

differences of wild compared to domesticated species of beans found that there was a large fraction of the genome of the common bean that appears to have been subjected to the effects of selection during

domestication Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. ...

. Domestication appears to have affected not only the target genes, but also a large portion of the genome around these genes. These "domestication islands" have probably experienced a higher level of isolation between the wild and the domesticated forms in comparison with the rest of the genome, probably because of linkage to the loci selected during domestication. In 2015, a study looked at the

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

sequences of pigs, and found that the assumption of reproductive isolation and strong domestication bottlenecks were incompatible with the data. The domestication process was assumed to have been initiated by humans, involved few individuals, and relied on reproductive isolation between wild and domestic forms. Despite gene flow between domestic and wild pigs, the genomes of domestic pigs had strong signatures of selection at loci that affect behavior and morphology. The conclusion was that recurrent selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars and created "islands of domestication" in the genome.

References

{{Genetics Genetics