Genomic consequences of colonisation, migration and genetic drift in barn owl insular populations of the eastern Mediterranean

The study of insular populations was key in the development of evolutionary theory. The successful colonisation of an island depends on the geographic context, and specific characteristics of the organism and the island, but also on stochastic processes. As a result, apparently identical islands may harbour populations with contrasting histories. Here, we use whole genome sequences of 65 barn owls to investigate the patterns of inbreeding and genetic diversity of insular populations in the eastern Mediterranean Sea. We focus on Crete and Cyprus, islands with similar size, climate and distance to mainland, that provide natural replicates for a comparative analysis of the impacts of microevolutionary processes on isolated populations. We show that barn owl populations from each island have a separate origin, Crete being genetically more similar to other Greek islands and mainland Greece, and Cyprus more similar to the Levant. Further, our data show that their respective demographic histories following colonisation were also distinct. On the one hand, Crete harbours a small population and maintains very low levels of gene flow with neighbouring populations. This has resulted in low genetic diversity, strong genetic drift, increased relatedness in the population and remote inbreeding. Cyprus, on the other hand, appears to maintain enough gene flow with the mainland to avoid such an outcome. Our work provides a comparative population genomic analysis of the effects of neutral processes on a classical island-mainland model system. It provides empirical evidence for the role of stochastic processes in determining the fate of diverging isolated populations.

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Major histocompatibility complex variation in insular populations of the Egyptian vulture: inferences about the roles of genetic drift and selection

Molecular Ecology ◽

10.1111/j.1365-294x.2011.05107.x ◽

2011 ◽

Vol 20 (11) ◽

pp. 2329-2340 ◽

Cited By ~ 28

Author(s):

ROSA AGUDO ◽

MIGUEL ALCAIDE ◽

CIRO RICO ◽

JESUS A. LEMUS ◽

GUILLERMO BLANCO ◽

...

Keyword(s):

Major Histocompatibility Complex ◽

Genetic Drift ◽

Major Histocompatibility ◽

Egyptian Vulture ◽

Histocompatibility Complex ◽

Complex Variation ◽

Insular Populations

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Food of the Barn Owl (Tyto alba) in the Eastern Mediterranean

Slovak Raptor Journal ◽

10.2478/v10262-012-0032-4 ◽

2009 ◽

Vol 3 (1) ◽

pp. 41-50 ◽

Cited By ~ 15

Author(s):

Ján Obuch ◽

Petr Benda

Keyword(s):

Eastern Mediterranean ◽

Rattus Rattus ◽

Passer Domesticus ◽

Barn Owl ◽

Tyto Alba ◽

Complex Evaluation ◽

Geographical Regions ◽

Meriones Tristrami ◽

Sample Set ◽

Prey Items

Food of the Barn Owl (Tyto alba) in the Eastern Mediterranean The composition of the Barn Owl (Tyto alba) diet analysed from pellets collected in several regions of the Eastern Mediterranean is presented. In total, 27 samples from 21 sites in S Italy, S Greece (incl. Crete), S Turkey, NW Syria, SW Lebanon, N Israel, and N Egypt were composed of 8842 prey individuals. Mammals represented the dominant part of the prey (90% of the identified prey individuals, comprising 44 species). Birds were less abundant (7%), however, their diversity was enormous (64 species). Amphibians and reptiles were rarely represented in the diet (0.9%), while invertebrates we found more often (2.2%). The relative abundance of particular prey items in the Barn Owl diet was analysed in four geographical regions: (a) SE Europe (Calabria, Peloponnese, Crete), (b) Levantine parts of Turkey and Syria, (c) Lebanon and N Israel, and (d) N Egypt. In complex evaluation of the sample set, endemic forms composed a special group of prey items: Microtus savii, Sorex samniticus, and Talpa romana in Calabria; Microtus thomasi in Peloponnese; Acomys minous in Crete; and Gerbillus amoenus in Egypt. Another group of prey is represented by typical Levantine species: Microtus guentheri, Meriones tristrami, Apodemus mystacinus, and Rana ridibunda. Apodemus flavicollis and Crocidura leucodon were more abundant in Calabria while less abundant in the Levant. Synanthropic mammals (Mus spp., Rattus rattus, Suncus etruscus, Crocidura suaveolens) and birds (Passer domesticus) represented a significant part of the diet in the majority of the studied area.

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Genetic-Variation Among Insular Populations of the Sleepy Lizard, Trachydosaurus-Rugosus Gray (Squamata, Scincidae)

Australian Journal of Zoology ◽

10.1071/zo9900603 ◽

1990 ◽

Vol 38 (6) ◽

pp. 603 ◽

Cited By ~ 15

Author(s):

S Sarre ◽

TD Schwaner ◽

A Georges

Keyword(s):

Genetic Variation ◽

Genetic Drift ◽

Allelic Diversity ◽

South Australia ◽

Allozyme Electrophoresis ◽

Specific Component ◽

Genetic Characteristics ◽

Island Populations ◽

Evolutionary Forces ◽

Insular Populations

Seven island populations of the sleepy lizard, Trachydosaurus rugosus, in South Australia were studied to establish the genetic effects of isolation. These effects were assessed by comparing genetic characteristics (using allozyme electrophoresis) of the island populations with those of three adjacent mainland populations. Heterozygosity levels did not vary significantly among the populations although the island populations exhibited reduced allelic diversity. Alleles that were rare on the mainland were not present in the island populations. Genetic divergence among the island populations was much greater than among populations on the mainland, reinforcing the notion that evolutionary forces, probably genetic drift, were greatest among the insular populations. This study demonstrates that the intra-specific component of variation can be significant, and that the importance of this component will increase with the fragmentation and isolation of populations. This finding serves to emphasis the importance of considering the population as the unit of conservation.

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