| 1. |
- Oliveira, E., et al.
(författare)
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High Levels of Hybridization between Molecular Forms of Anopheles gambiae from Guinea Bissau
- 2008
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Ingår i: Journal of medical entomology. - 0022-2585 .- 1938-2928. ; 45:6, s. 1057-1063
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Tidskriftsartikel (refereegranskat)abstract
- In the malaria vector Anopheles gambiae Giles sensu stricto, two molecular forms denoted M and S are considered units of incipient speciation within this species. Very low hybrid frequencies and significant genetic differentiation have been found in sympatric M- and S-form populations, We studied the molecular form composition and the degree of genetic differentiation at 15 microsatellites in two samples of An. gambiae collected ill two consecutive years from Bissau, Guinea Bissau. High frequencies of M/S hybrids (19-24%) were found in this area. Coincidently, very low levels of genetic differentiation were detected between forms when analysis involved microsatellites mapped at chromosome-3 (mean F-st 0.000-0.002). The single exception was the X-linked AGXH678, for which high differentiation was measured (F-st 0.158-0.301). This locus maps near the centromere of chromosome X, a low recombination region in which selection is likely to promote divergence between M and S forms. These results strongly suggest that the degree of isolation between M and S forms, considered the units of incipient speciation within An. gambiae, is not homogenous throughout the species distribution range.
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| 2. |
- Leonard, Jennifer A, et al.
(författare)
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A rapid loss of stripes : the evolutionary history of the extinct quagga.
- 2005
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Ingår i: Biol Lett. - 1744-9561. ; 1:3, s. 291-5
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Tidskriftsartikel (refereegranskat)abstract
- Twenty years ago, the field of ancient DNA was launched with the publication of two short mitochondrial (mt) DNA sequences from a single quagga (Equus quagga) museum skin, an extinct South African equid (Higuchi et al. 1984 Nature312, 282-284). This was the first extinct species from which genetic information was retrieved. The DNA sequences of the quagga showed that it was more closely related to zebras than to horses. However, quagga evolutionary history is far from clear. We have isolated DNA from eight quaggas and a plains zebra (subspecies or phenotype Equus burchelli burchelli). We show that the quagga displayed little genetic diversity and very recently diverged from the plains zebra, probably during the penultimate glacial maximum. This emphasizes the importance of Pleistocene climate changes for phylogeographic patterns in African as well as Holarctic fauna.
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