Hybridization Leads to Speciation

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Hybridization Leads to Speciation:

Hybridization Leads to Speciation Aditya Rai Biology 7

Speciation:

Speciation - Process by which new species arise. -Has been a major part of evolutionary biology. -Modes of Speciation: A) Allopatric B) Peripatric C) Parapatric D) Sympatric

Speciation:

Speciation

Allopatric Speciation:

Allopatric Speciation - Speciataition by geographic isolation.

Peripatric Speciation:

Peripatric Speciation -Isolated indivduals decrease in size causing a small population size. -Genetic drift acts faster in small populations. -Genetic drift can lead to speciation.

Parapatric Speciation:

Parapatric Speciation - Continuous growth of population. -No random mating. -Individuals are likely to mate with geographic neighbors, due to certain pressures, which can lead to speciation. -Hybrids would form due to interbreeding.

Sympatric Speciation :

Sympatric Speciation -A species arises from another species from the same environment. -This happens due to a change in the individuals niche and specifically adapts to that niche. -This is different from allopatric speciation because it happens in the same environment.

Hybrid Speciation:

Hybrid Speciation -Two closely related species breed and make a new species that is reproductively isolated from the parent species. -Fairly common in plants. -From the 1940s it was difficult to isolate the reproductive genes from offspring and parents so hybridization seemed very rare. -In the 1990s when reproductive isolation was more advanced hybridization was found to be a very common phenomenon. (Especially in plants)

Introgression or Introgressive Hybridization:

Introgression or Introgressive Hybridization -Movement of genes from one species to the other by the means of backcrossing hybrid with its parent. -Has major effects in the sympatric mode. -A much more complex process than simple hybridization.

Genealogy:

Genealogy 5/7/13

Gene Distribution:

Gene Distribution 5/7/13

References:

References Camilo Salazar, Simon W. Baxter, Carolina Pardo-Diaz, Grace Wu, Alison Surridge, Mauricio Linares, Eldredge Bermingham, Chris D. Jiggins. 2010. Genetic Evidence for Hybrid Trait Speciation in Heliconius Butterflies. PLoS Genet. 6:e1000930. doi: 10.1371/journal.pgen.1000930. Sebastien Deregnaucourt. 2010. Interspecific Hybridization as a Tool to Understand Vocal Divergence: The Example of Crowing in Quail (GenusCoturnix). PLoS One. 5: e9451. doi:10.1371/journal.pone.0009451 5/7/13

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