Genetic diversity and inter-specific relations of western Mediterranean relic Abies taxa as compared to the Iberian A. alba

Abstract

Several Abies species are currently present in the Mediterranean Region and most of them are endemits and Tertiary relicts. Using six nuclear microsatellites, we studied the genetic structure and inter-specific relationships among West Mediterranean firs, A. pinsapo (Spain), A. maroccana and A. tazaotana (Morocco). Based on the hypothesis that A. pinsapo could historically exchange genes with A. alba growing in the Pyrenees via secondary contact, we investigated the level of genetic admixture between these species using a Bayesian approach.The studied populations showed moderate genetic diversity (mean H E = 0.598) and a high level of genetic differentiation (F ST = 0.225) that was especially pronounced between A. alba and African firs. All populations experienced a strong bottleneck effect that was likely induced by climatic changes occurring in the west Mediterranean during the last glacial cycle and the Holocene. According to Bayesian clustering, both African taxa grouped together in a single cluster, the two A. pinsapo populations formed a second cluster, and two additional clusters were detected within A. alba. Our results indicate that A. tazaotana is genetically very close to A. maroccana, and hence these two taxa should probably not be considered as separate species. We found no genetic admixture between A. pinsapo and A. alba and only minor between A. pinsapo and African fir populations suggesting an isolation effect of the Gibraltar Strait. Current limited distributions of firs in the Mediterranean Region together with changing climate may lead to further deterioration of the genetic diversity levels. Hence, future efforts should focus on monitoring the demography and genetic threats to existing populations.

Effect of the Aegean Sea barrier between Europe and Asia on differentiation inJuniperus drupacea(Cupressaceae)

“…The level of genetic diversity of J. drupacea was relatively high, but was comparable to that exhibited by other taxa of Cupressaceae and of gymnosperms in general, estimated with a different set of genetic markers (e.g. Meloni et al ., ; Michalczyk et al ., ; Provan et al ., ; Terrab et al ., ; Douaihy et al ., ; Dzialuk et al ., ; Yücedağ & Gailing, ; Dering et al ., ; Teixeira, Rodríguez‐Echeverría & Nabais, ; Sękiewicz et al ., ). The values of H E for J. oxycedrus , using the same three markers, were similar (compare Table to Boratyński et al ., : table 1).…”

“…In the western Mediterranean basin, the Strait of Gibraltar, which opened at the end of the Messinian (c. 5.3 Mya; Krijgsman et al, 1999), is commonly recognized as a significant biogeographic barrier that caused vicariant speciation processes in the European and African parts of the geographical ranges of several taxa (e.g. Terrab et al, 2007Terrab et al, , 2008Rodr ıguez-S anchez et al, 2008;Dzialuk et al, 2011;Se z kiewicz et al, 2013;Boraty nski et al, 2013;Dering et al, 2014;S anchez-Robles et al, 2014). In the eastern Mediterranean basin, there was no such restricted isolation between Europe and Asia.…”

Unexpected scenarios from Mediterranean refugial areas: disentangling complex demographic dynamics along the Apennine distribution of silver fir

“…S1.4). Assuming a generation time of 50 years (Liepelt et al, 2002;Dering et al, 2014;Ruosch et al, 2016), these values can be translated into 66000 (95% CI: 15500-155500), 237500 (95% CI: 90000-342500), 389500 (95% CI: 211500-493000), 600000 yrs bp (95% CI: 347500-740000) for t 1 , t 2 , t 3 , and t 4 respectively.…”

Effect of geographic range discontinuity on species differentiation—East-Mediterranean Abies cilicica: a case study

“…However, our results are not final, mainly because nSSR-based genetic patterns do not have to follow taxonomic entities. There are some studies in which these kinds of markers helped to resolve taxonomic doubts or give some new insights (Boratyński et al 2014;Dering et al 2014), but generally reliable phylogenetic analysis requires the use of more appropriate markers and statistical tools.…”