Search results
Results from the WOW.Com Content Network
Introgression is an important source of genetic variation in natural populations and may contribute to adaptation and even adaptive radiation. [7] It can occur across hybrid zones due to chance, selection or hybrid zone movement. [8]
Hybridization without change in chromosome number is called homoploid hybrid speciation. [1] This is the situation found in most animal hybrids. For a hybrid to be viable, the chromosomes of the two organisms will have to be very similar, i.e., the parent species must be closely related, or else the difference in chromosome arrangement will ...
Eukaryote hybrid genomes result from interspecific hybridization, where closely related species mate and produce offspring with admixed genomes.The advent of large-scale genomic sequencing has shown that hybridization is common, and that it may represent an important source of novel variation.
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 ...
Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosome number; the result is progeny which are immediately reproductively isolated from the parent population. New species can also be created through hybridization, followed by reproductive isolation, if the hybrid is favoured by natural selection.
Through another approach—using one genome each of a Neanderthal, Eurasian, African, and chimpanzee (outgroup), and dividing it into non-recombining short sequence blocks—to estimate genome-wide maximum-likelihood under different models, an ancient population sub-structure in Africa was ruled out and a Neanderthal admixture event was confirmed.
There is some evidence of adaptive evolution in genes linked to brain development, but some of these genes are often associated with diseases, e.g. microcephaly (see Table 2). However, there is a particular interest in the search for adaptive evolution in brain genes, despite the ethical issues surrounding such research.
These masterful studies provided concrete support for the theory of natural selection, at the same time illustrating the fruitfulness of combining field and laboratory work in the study of evolution. [17] Adaptive evolution occurs through the dominance and survival of competing genes within a species.