RESUMEN
Assessing the degree of genetic diversity and differentiation of rare or endangered endemic species is essential to evaluate the conservation status of populations and successively implement appropriate conservation strategies. We investigated the population structure of Salvia ceratophylloides Ard., a scapose hemicryptophyte endemic to Calabria (southern Italy), both to answer questions about its genetic structure and to determine whether the actual population size has undergone significant demographic changes in the near past. The data obtained from the census showed that the populations are characterised by a greater number of adult individuals than juveniles and are on declining. The genetic analysis carried out on 99 individuals from four populations of the species under study, shows a mean expected heterozygosity value of 0.50 and an overall differentiation value of 0.083. The population structure shows that the four studied populations are distinct genetic units, genetically linked to four different ancestral gene pools. Bayesian analysis based on ABC models indicates that the present populations underwent a significant reduction in size in the past. This corresponds to the demographic decline at the end of the 19th century, which according to the literature, was due to the strong anthropic pressure (agriculture, grazing, fire and plantations) of Reggio Calabria suburbs. We can therefore conclude that populations are not affected by inbreeding and low genetic diversity and that there is no immediate danger of genetic erosion, and that the problems associated with population decline, past and present, are exclusively due to anthropogenic causes.
RESUMEN
The sweet chestnut (Castanea sativa Mill.) is subject to the progressive disappearance of its traditional chestnut groves. In the northern part of Italy, where distribution of the sweet chestnut is fragmented, many local varieties continue to be identified mostly by oral tradition. We characterised by SSRs eleven historically recognised varieties of sweet chestnut in the area surrounding Lake Como, with the goal of giving a genetic basis to the traditional classification. We performed classical analysis about differentiation and used Bayesian approaches to detect population structure and to reconstruct demography. The results revealed that historical and genetic classifications are loosely linked when chestnut fruits are just "castagne", that is, normal fruits, but increasingly overlap where "marroni" (the most prized fruits) are concerned. Bayesian classification allowed us to identify a homogeneous gene cluster not recognised in the traditional assessment of the varieties and to reconstruct possible routes used for the propagation of sweet chestnut. We also reconstructed ancestral relationships between the different gene pools involved and dated ancestral lineages whose results fit with palynological data. We suggest that conservation strategies based on a genetic evaluation of the resource should also rely on traditional cultural heritage, which could reveal new sources of germplasm.
Asunto(s)
Fagaceae , Fagaceae/genética , Fagaceae/clasificación , Italia , Repeticiones de Microsatélite/genética , Teorema de Bayes , FilogeniaRESUMEN
Lions (Panthera leo) play a crucial ecological role in shaping and maintaining fragile ecosystems within Africa. Conservation efforts should focus on genetic variability within wild populations when considering reintroduction attempts. We studied two groups of lions from two conservation sites located in Zambia and Zimbabwe to determine their genetic make-up, information that is usually unknown to the sites. In this study, we analysed 17 specimens for cytb and seven microsatellite markers to ascertain family relationships and genetic diversity previously obtained by observational studies. We then produced a standardised haplogroup phylogeny using all available entire mitogenomes, as well as calculating a revised molecular clock. The modern lion lineage diverged ~151 kya and was divided into two subspecies, both containing three distinct haplogroups. We confirm that Panthera leo persica is not a subspecies, but rather a haplogroup of the northern P.l. leo that exited Africa at least ~31 kya. The progenitor to all lions existed ~1.2 Mya, possibly in SE Africa, and later exited Africa and split into the two cave lion lineages ~175 kya. Species demography is correlated to major climactic events. We now have a detailed phylogeny of lion evolution and an idea of their conservation status given the threat of climate change.
Asunto(s)
Genoma Mitocondrial , Leones , Filogenia , Animales , Leones/genética , Leones/clasificación , Genoma Mitocondrial/genética , Cuevas , Variación Genética , Haplotipos , Repeticiones de Microsatélite/genética , Pradera , Zimbabwe , Evolución Molecular , Zambia , Citocromos b/genética , ADN Mitocondrial/genéticaRESUMEN
The Turkey oak (Quercus cerris L.) is widely distributed in Italy, where it is the ecologically dominant oak on sandy and acidic soil. In this work, we analysed 23 natural populations by means of eight SSR (microsatellite) markers, to obtain the first synthetic map of genetic variability for this species and to study its dispersion during the Holocene, due to the possibility that at least one refugium during the Last Glacial Maximum was in Italy. The analyses showed a good amount of genetic variability together with fair differentiation between populations, as indicated by FST = 0.059. A Bayesian analysis of the amount of admixture among populations revealed the presence of four putative gene pools of origin and a rough subdivision of the populations according to their geographic location, as confirmed by the spatial analysis. No evidence for the existence of putative refugial populations was found; however, this study paves the way for the planning of conservation strategies also with regard to the relationship between Turkey oak and other oak species in Italy.