Molecular genetic differentiation of native populations of Mediterranean blue mussels, Mytilus galloprovincialis Lamarck, 1819, and the relationship with environmental variables

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Faeces as a source of DNA for molecular studies in a threatened population of great bustards

With recent advances in molecular biology, it is now possible to use the trace amounts of DNA in faeces to non-invasively sample endangered species for genetic studies. A highly vulnerable population of approximately 100 great bustards (Otis tarda) exists in Morocco necessitating the use of non-invasive protocols to study their genetic structure. Here we report a reliable silica-based method to extract DNA from great bustard faeces. We found that successful extraction and amplification correlated strongly with faeces freshness and composition. We could not extract amplifiable DNA from 30% of our samples as they were dry or contained insect material. However 100% of our fresh faecal samples containing no obvious insect material worked, allowing us to assess the levels of genetic variation among 25 individuals using a 542 bp control region sequence. We were able to extract DNA from four out of five other avian species, demonstrating that faeces represents a suitable source of DNA for population genetics studies in a broad range of species

Mitochondrial control region diversity of the houbara bustard Chlamydotis undulata complex and genetic structure along the Atlantic seaboard of North Africa

The houbara bustard, Chlamydotis undulata, is a declining cryptic desert bird whose range extends from North Africa to Central Asia. Three subspecies are currently recognized by geographical distribution and morphology: C.u.fuertaventurae, C.u.undulata and C.u.macqueenii. We have sequenced 854 bp of mitochondrial control region from 73 birds to describe their population genetic structure with a particular sampling focus on the connectivity between C.u.fuertaventurae and C.u.undulata along the Atlantic seaboard of North Africa. Nucleotide and haplotypic diversity varied among the subspecies being highest in C.u.undulata, lowest in C.u.fuertaventurae and intermediate in C.u.macqueenii. C.u.fuertaventurae and C.u.undulata are paraphyletic and an average nucleotide divergence of 2.08% splits the later from C.u.macqueenii. We estimate that C.u.fuertaventurae and C.u.undulata split from C.u.macqueenii approximately 430 000 years ago. C.u.fuertaventurae and C.u.undulata are weakly differentiated (F-ST = 0.27, N-m = 1.3), indicative of a recent shared history. Archaeological evidence indicates that houbara bustards have been present on the Canary Islands for 130-170 000 years. However, our genetic data point to a more recent separation of C.u.fuertaventurae and C.u.undulata at around 20-25 000 years. Concordant archaeological, climatic opportunities for colonization and genetic data point to a scenario of: (i) initial colonization of the Canary Islands about 130 000 years ago; (ii) a period of secondary contact 19-30 000 years ago homogenizing any pre-existing genetic structure followed by; (iii) a period of relative isolation that persists today

Gene flow in great bustard populations across the Strait of Gibraltar as elucidated from excremental PCR and mtDNA sequencing

Recent advances in molecular biology have made it possible to use the trace amounts of DNA in faeces to non-invasively sample endangered species for genetic studies. Here we use faeces as a source of DNA and mtDNA sequence data to elucidate the relationship among Spanish and Moroccan populations of great bustards. 834 bp of combined control region and cytochrome-b mtDNA fragments revealed four variable sites that defined seven closely related haplotypes in 54 individuals. Morocco was fixed for a single mtDNA haplotype that occurs at moderate frequency (28%) in Spain. We could not differentiate among the sampled Spanish populations of Caceres and Andalucia but these combined populations were differentiated from the Moroccan population. Estimates of gene flow (Nm = 0.82) are consistent with extensive observations on the southern Iberian peninsular indicating that few individuals fly across the Strait of Gibraltar. We demonstrate that both this sea barrier and mountain barriers in Spain limit dispersal among adjacent great bustard populations to a similar extent. The Moroccan population is of high ornithological significance as it holds the only population of great bustards in Africa. This population is critically small and genetic and observational data indicate that it is unlikely to be recolonised via immigration from Spain should it be extirpated. In light of the evidence presented here it deserves the maximum level of protection