Search results
Results from the WOW.Com Content Network
Hybrid zones can form from secondary contact. A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. . Hybrid zones can form in situ due to the evolution of a new lineage [1] [page needed] but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their ...
A hybrid zone may appear during secondary contact, meaning there would be an area where the two populations cohabitate and produce hybrids, often arranged in a cline. The width of the zone may vary from tens of meters to several hundred kilometers. A hybrid zone may be stable, or it may not.
It can occur across hybrid zones due to chance, selection or hybrid zone movement. [8] There is evidence that introgression is a ubiquitous phenomenon in plants and animals, [9] [10] including humans, [11] in which it may have introduced the microcephalin D allele. [12]
In a tension zone there is the increased probability of hybridization between species of the separate zones and thus the tension zone may also be a hybrid zone. [6] Historically tension zones were entirely natural in origin, however human activity has altered the tension zones in a variety of areas all over the world. [7]
Hybrizyme is a term coined to indicate novel or normally rare gene variants (or alleles) that are associated with hybrid zones, geographic areas where two related taxa (e.g. species or subspecies) meet, mate, and produce hybrid offspring. [1] The hybrizyme phenomenon is widespread and these alleles occur commonly, if not in all hybrid zones. [2]
Mathematical models, laboratory studies, and observational evidence supports the existence of parapatric speciation's occurrence in nature. The qualities of parapatry imply a partial extrinsic barrier during divergence; [2] thus leading to a difficulty in determining whether this mode of speciation actually occurred, or if an alternative mode (notably, allopatric speciation) can explain the data.
This can be referred to as a mosaic hybrid zone. [8] A mosaic hybrid zone occurs because the habitat ranges for A. fasciatus and A. socius overlap. [9] While it is known that for the most part A. fasciatus remains separated from A. socius when breeding, the potential for interbreeding can occur. [6]
Reinforcement can also occur in single populations, [29] [23] mosaic hybrid zones (patchy distributions of parental forms and subpopulations), [31] and in parapatric populations with narrow contact zones. [33] Population densities are an important factor in reinforcement, often in conjunction with extinction. [23]