GEOGRAPHICAL PATTERNS OF GENETIC DIFFERENTIATION IN THE LANDSNAIL HELIX ASPERSA MuLLER (GASTROPODA: PULMONATA)

In order to investigate the initial processes responsible forthe geographical distribution of the Mediterranean landsnailHelix aspersa, populations from 64 locations in Maghreb andin Europe were studied at 17 enzyme loci by both starch andpolyacrylamide gel electrophoresis. Allele frequencies and genotypedistributions were analysed to provide information on populationstructure and genetic differentiation among populations. Valuesof Nei's unbiased (D) and Rogers (R) genetic distances led tothe formation of two main groups, namely Europe-west Algeriaand east Maghreb (average D = 0.182). Such splitting supportedthe pattern of anatomical variation recently described. Twosamples from Morocco were excluded from these groups becauseof an average D = 0.224. Within this Moroccan entity, geneticdivergences did not distinguish the ‘giant’ snailsH. a.maxima from the brownsnails H. a. aspersa. Such biochemicalsimilarities among morphological heterogeneity throws the subspecificstatus of H. a. maxima into question. Values of fixation indicesindicated that the greatest differentiation between samplesoccurred on the Maghreb territory ( = 0.393). The patterns of population differentiation are discussed inrelation to past geological and historical events. Thus, threescenarios, not mutually exclusive, are considered: the disjunctionof populations by plate tectonics during the Tertiary, the formationof geographically isolated populations during the Pleistoceneglacial/interglacial cycle and the possibility of human introductionas early as the Neolithic period. (Received 9 December 1992; accepted 11 November 1993)     

Genetic diversity of Moroccan grape accessions conserved ex situ compared to Maghreb and European gene pools

Grape diversity present in Morocco and the part of this diversity used nowadays are poorly documented. In order to choose diversified genotypes, to select them so that their agronomic interest will be tested, a group of 21 autochthonous cultivars preserved in the germplasm collections of SODEA and 18 Moroccan cultivars from “Domaine de Vassal” INRA grape collection was compared to a group of cultivars from neighbouring countries (Algeria and Tunisia), and from a core collection optimizing simple sequence repeat (SSR) allelic diversity of grape. Data from 20 nuclear and 3 chloroplastic SSR markers were obtained for this set of 211 cultivars. A total of 156 alleles (mean of 7.8 alleles per locus) were detected for the nSSRs and 7 alleles for the cpSSR in the Moroccan group. Chlorotype diversity in Moroccan and Algerian group were similar, but slightly lower than in the Tunisian group and the core collection. Similarly, the nSSR diversity was high in the core collection and low in the Moroccan and the Algerian groups compared to the two other groups. Clustering of cultivars based on nSSR data reflected their geographical origin and, to a certain extent, the use of the cultivars. The specificity of the Moroccan plant material was attested by the Bayesian analysis using Structure, while differences of the core collection were clearly revealed both by the Bayesian and a multivariate analysis. These results confirm the differentiation of the material from Maghreb and more specifically of Moroccan material, having evolved independently from Europe.     

The impact of the Austronesian expansion: evidence from mtDNA and Y chromosome diversity in the Admiralty Islands of Melanesia

The genetic ancestry of Polynesians can be traced to both Asia and Melanesia, which presumably reflects admixture occurring between incoming Austronesians and resident non-Austronesians in Melanesia before the subsequent occupation of the greater Pacific; however, the genetic impact of the Austronesian expansion to Melanesia remains largely unknown. We therefore studied the diversity of nonrecombining Y chromosomal (NRY) and mitochondrial (mt) DNA in the Admiralty Islands, located north of mainland Papua New Guinea, and updated our previous data from Asia, Melanesia, and Polynesia with new NRY markers. The Admiralties are occupied today solely by Austronesian-speaking groups, but their human settlement history goes back 20,000 years prior to the arrival of Austronesians about 3,400 years ago. On the Admiralties, we found substantial mtDNA and NRY variation of both Austronesian and non-Austronesian origins, with higher frequencies of Asian mtDNA and Melanesian NRY haplogroups, similar to previous findings in Polynesia and perhaps as a consequence of Austronesian matrilocality. Thus, the Austronesian language replacement on the Admiralties (and elsewhere in Island Melanesia and coastal New Guinea) was accompanied by an incomplete genetic replacement that is more associated with mtDNA than with NRY diversity. These results provide further support for the "Slow Boat" model of Polynesian origins, according to which Polynesian ancestors originated from East Asia but genetically mixed with Melanesians before colonizing the Pacific. We also observed that non-Austronesian groups of coastal New Guinea and Island Melanesia had significantly higher frequencies of Asian mtDNA haplogroups than of Asian NRY haplogroups, suggesting sex-biased admixture perhaps as a consequence of non-Austronesian patrilocality. We additionally found that the predominant NRY haplogroup of Asian origin in the Admiralties (O-M110) likely originated in Taiwan, thus providing the first direct Y chromosome evidence for a Taiwanese origin of the Austronesian expansion. Furthermore, we identified a NRY haplogroup (K-P79, also found on the Admiralties) in Polynesians that most likely arose in the Bismarck Archipelago, providing the first direct link between northern Island Melanesia and Polynesia. These results significantly advance our understanding of the impact of the Austronesian expansion and human history in the Pacific region.     

Phylogeographical footprints of the Strait of Gibraltar and Quaternary climatic fluctuations in the western Mediterranean: a case study with the greater white-toothed shrew, Crocidura russula (Mammalia: Soricidae)

We used mitochondrial cyt b sequences to investigate the phylogenetic relationships of Crocidura russula (sensu lato) populations across the Strait of Gibraltar, western Europe, Maghreb, and the Mediterranean and Atlantic islands. This revealed very low genetic divergence between European and Moroccan populations. The application of a molecular clock previously calibrated for shrews suggested that the separation of European from Moroccan lineages occurred less than 60 000 bp, which is at least 5 million years (Myr) after the reopening of the Strait of Gibraltar. This means that an overwater dispersal event was responsible for the observed phylogeographical structure. In contrast, genetic analyses revealed that Moroccan populations were highly distinct from Tunisian ones. According to the molecular clock, these populations separated about 2.2 million years ago (Ma), a time marked by sharp alternations of dry and humid climates in the Maghreb. The populations of the Mediterranean islands Ibiza, Pantelleria, and Sardinia were founded from Tunisian populations by overwater dispersal. In conclusion, overwater dispersal across the Strait of Gibraltar, probably assisted by humans, is possible for small terrestrial vertebrates. Moreover, as in Europe, Quaternary climatic fluctuations had a major effect on the phylogeographical structure of the Maghreb biota.     

Pleistocene diversification in Morocco and recent demographic expansion in the Mediterranean pond turtle Mauremys leprosa

Quaternary climatic oscillations and geographic barriers have strongly influenced the distribution and diversification of thermophilic species occurring in the Mediterranean Basin. The Western Mediterranean pond turtle, Mauremys leprosa, is widely distributed throughout the Iberian Peninsula, southern France and most of the Maghreb region, with two subspecies currently recognized. In this work, we used 566 samples, including 259 new individuals, across the species range, and sequenced two mitochondrial markers (cytochrome b gene and control region; 163 samples in a concatenated mtDNA dataset) and one nuclear intron (R35; 23 samples representing all identified sublineages) to study the evolutionary history of M. leprosa. We combined phylogenetic methods and phylogeographic continuous diffusion models with spatial analysis. Our results (1) show a high level of genetic structure in Morocco originated during the Pleistocene; (2) reveal two independent population expansion waves from Morocco to Tunisia and to southern Europe, which later expanded throughout the Iberian Peninsula, and (3) identify several secondary contact zones in Morocco. Our study also sheds new light on the role of geographical features (Moroccan mountains ranges and the Strait of Gibraltar) and Pleistocene climatic oscillations in shaping genetic diversity and structure of M. leprosa, and underlines the importance of the Maghreb as a differentiation centre harbouring distinct glacial refugia.     

High levels of Y-chromosome differentiation among native Siberian populations and the genetic signature of a boreal hunter-gatherer way of life

We examined genetic variation on the nonrecombining portion of the Y chromosome (NRY) to investigate the paternal population structure of indigenous Siberian groups and to reconstruct the historical events leading to the peopling of Siberia. A set of 62 biallelic markers on the NRY were genotyped in 1432 males representing 18 Siberian populations, as well as nine populations from Central and East Asia and one from European Russia. A subset of these markers defines the 18 major NRY haplogroups (A-R) recently described by the Y Chromosome Consortium (YCC 2002). While only four of these 18 major NRY haplogroups accounted for -95% of Siberian Y-chromosome variation, native Siberian populations differed greatly in their haplogroup composition and exhibited the highest phiST value for any region of the world. When we divided our Siberian sample into four geographic regions versus five major linguistic groupings, analyses of molecular variance (AMOVA) indicated higher phiST and phiCT values for linguistic groups than for geographic groups. Mantel tests also supported the existence of NRY genetic patterns that were correlated with language, indicating that language affiliation might be a better predictor of the genetic affinity among Siberians than their present geographic position. The combined results, including those from a nested cladistic analysis, underscored the important role of directed dispersals, range expansions, and long-distance colonizations bound by common ethnic and linguistic affiliation in shaping the genetic landscape of Siberia. The Siberian pattern of reduced haplogroup diversity within populations combined with high levels of differentiation among populations may be a general feature characteristic of indigenous groups that have small effective population sizes and that have been isolated for long periods of time.     

Maintaining the genetic health of putative Barbary lions in captivity: an analysis of Moroccan Royal Lions

The last representatives of the Barbary lion (Panthera leo leo), once numerous in North Africa but exterminated from the wild by the 1940s, are believed to be the captive lions descended from the Moroccan Royal Collection, numbering less than 90 animals in zoos worldwide. The genetic fitness of these captive “Royal Lions” may now be under threat since, although most zoos have avoided hybridisation with animals of other origin, no formal breeding programme currently exists and several institutions have halted breeding activities. This situation has arisen since the distinctiveness of Barbary lions and the representative status of Royal Lions remain inconclusive and definitive molecular studies have yet to be completed. Previously, in the 1970s, morphological and phenotypic traits were used to match Royal Lions and the historic Barbary lion and an ex situ breeding programme was initiated involving a number of selected “founder” animals. This paper outlines the status of the descendent population within zoos in Morocco and Europe, including all known pure-bred descendents from the Royal Palace collection. Founder representation is shown to be greater across European collections than the Moroccan collection. Breeding exchanges are recommended between institutions in order to improve genetic diversity and maintain the genetic health of the population and a studbook for European zoo animals has been developed to support this action. This analysis serves as a benchmark for guiding effective maintenance of the captive population, thereby allowing time to clarify the conservation value of Royal Lions and their relevance to North African ecology.     

Investigating sex‐specific dynamics using uniparental markers: West New Guinea as a case study

Mitochondrial DNA (mtDNA) and Y chromosome (NRY) genetic markers have been often contrasted to investigate sex‐specific dynamics. Traditionally, isolation by distance, intrapopulation genetic diversity and population differentiation are estimated from both markers and compared. Two possible sources of bias are often neglected. First, kilometric distances are frequently used as predictor of the connectivity between groups, hiding the role played by environmental features at a microgeographic scale. Second, the comparison of intrapopulation diversity and population differentiation between mtDNA and NRY is hampered by their different mutational mechanisms and rates. Here, we show how to account for these biases by analyzing from a different perspective a published dataset of eight West New Guinea (WNG) populations for which mtDNA control region sequences and seven linked NRY microsatellites had been typed. First, we modeled the connectivity among sampled populations by computing the number of days required to travel between groups. Then, we investigated the differences between the two sexes accounting for the molecular characteristics of the markers examined to obtain estimates on the product of the effective population size and the migration rate among demes (Nm). We achieved this goal by studying the shape of the gene genealogy at several sampling levels and using spatial explicit simulations. Both the direction and the rate of migration differ between male and females, with an Nm estimated to be >6 times higher in the latter under many evolutionary scenarios. We finally highlight the importance of applying metapopulation models when analyzing the genetic diversity of a species.     

Area prioritization and performance evaluation of the conservation area network for the Moroccan herpetofauna: a preliminary assessment

The integration of spatial area prioritization algorithms and species distribution modelling has shown great promise in conservation planning in recent years. However, despite the fact that reptiles and amphibians have the highest threat status of all terrestrial vertebrates, these species are often under-represented in conservation planning. The Kingdom of Morocco possesses the richest and most varied herpetofauna in the Maghreb and the western Mediterranean, and is characterized by high species richness, endemism and number of European relict species. Despite the fact that Moroccan reptiles and amphibians have been the subject of numerous studies by a large number of international herpetologists since the beginning of the 20th century, few or none of these concerned their conservation. This study had three main objectives: (1) to identify those areas that harbour the highest species richness; (2) to evaluate the existing and proposed future ‘important biological and ecological sites’ (SIBES) conservation area network (CAN) with respect to their ability to protect the herpetofauna adequately; and (3) to identify priority areas into which the existing protected areas can be augmented. We used maximum-entropy species distribution modelling to run distribution models for 11 amphibian and 86 reptile species (27.6% endemics and 12.4% threatened) for which we had 2,170 single geographic records. A total of 97 models were used to create a richness map of the Moroccan herpetofauna and thereby detect both areas of high species richness and the distribution patterns of individual species. This map was subsequently used as a basis for performance evaluation of the CAN and area prioritization using the ConsNet conservation planning software initialized by “Rarity” first, while using representation targets of 5% and 10%. Additionally, the proposed future Moroccan CAN (SIBES) was evaluated in terms of its overlay and proximity with ConsNet solutions using visual interpretation and distance measurements in a GIS. Our results show that Moroccan herpetofauna is poorly protected under the existing and future CAN. Prioritization of areas shows that a major increase in conservation area is required to guarantee the persistence of individual herpetofauna species even with a global minimum representation target of only 10%. An increase of the existing CAN is especially needed along parts of the Atlantic coast, in the north-western Mediterranean region, on the north-eastern Moroccan coast, as well as in several areas in the Sahara, notably vast proportions of the Vallée du Haut and Bas Draa.     

Melanesian and Asian origins of Polynesians: mtDNA and Y chromosome gradients across the Pacific

The human settlement of the Pacific Islands represents one of the most recent major migration events of mankind. Polynesians originated in Asia according to linguistic evidence or in Melanesia according to archaeological evidence. To shed light on the genetic origins of Polynesians, we investigated over 400 Polynesians from 8 island groups, in comparison with over 900 individuals from potential parental populations of Melanesia, Southeast and East Asia, and Australia, by means of Y chromosome (NRY) and mitochondrial DNA (mtDNA) markers. Overall, we classified 94.1% of Polynesian Y chromosomes and 99.8% of Polynesian mtDNAs as of either Melanesian (NRY-DNA: 65.8%, mtDNA: 6%) or Asian (NRY-DNA: 28.3%, mtDNA: 93.8%) origin, suggesting a dual genetic origin of Polynesians in agreement with the "Slow Boat" hypothesis. Our data suggest a pronounced admixture bias in Polynesians toward more Melanesian men than women, perhaps as a result of matrilocal residence in the ancestral Polynesian society. Although dating methods are consistent with somewhat similar entries of NRY/mtDNA haplogroups into Polynesia, haplotype sharing suggests an earlier appearance of Melanesian haplogroups than those from Asia. Surprisingly, we identified gradients in the frequency distribution of some NRY/mtDNA haplogroups across Polynesia and a gradual west-to-east decrease of overall NRY/mtDNA diversity, not only providing evidence for a west-to-east direction of Polynesian settlements but also suggesting that Pacific voyaging was regular rather than haphazard. We also demonstrate that Fiji played a pivotal role in the history of Polynesia: humans probably first migrated to Fiji, and subsequent settlement of Polynesia probably came from Fiji.     

Comparison of genetic diversity (RAPD) of ex situ collections and natural populations of Naufraga balearica Constance & Cannon

Naufraga balearica Constance & Cannon (Hydrocotyloideae) cultivated in the Botanical Gardens of Lyon, Brest and Porquerolles stem from two or three shoots collected in Corsica in 1981. The genetic diversity of these plants was evaluated using RAPD markers (random amplified polymorphic DNA). It was compared with the diversity found in individuals collected from five natural sites in Majorca. Only a few patterns were present in the collections derived from the Corsican shoots. The plants kept in the Botanical Gardens appeared to be of clonal origin: most individuals (81%) showed a 'dominant pattern'. In contrast, nearly all individuals sampled in the natural populations of the Balearic Islands exhibited a unique pattern. The five populations appeared genetically distinct; the individuals probably resulted from cross-fertilizations. The cultivated Corsican plants from Lyon, Brest and Porquerolles appeared genetically closely related to the individuals sampled in the population of Cala San Vicente in Majorca. The spontaneity of this paleoendemic in Corsica was discussed.     

Evaluation of Group Genetic Ancestry of Populations from Philadelphia and Dakar in the Context of Sex-Biased Admixture in the Americas

Background

Population history can be reflected in group genetic ancestry, where genomic variation captured by the mitochondrial DNA (mtDNA) and non-recombining portion of the Y chromosome (NRY) can separate female- and male-specific admixture processes. Genetic ancestry may influence genetic association studies due to differences in individual admixture within recently admixed populations like African Americans.

Principal Findings

We evaluated the genetic ancestry of Senegalese as well as European Americans and African Americans from Philadelphia. Senegalese mtDNA consisted of ∼12% U haplotypes (U6 and U5b1b haplotypes, common in North Africa) while the NRY haplotypes belonged solely to haplogroup E. In Philadelphia, we observed varying degrees of admixture. While African Americans have 9–10% mtDNAs and ∼31% NRYs of European origin, these results are not mirrored in the mtDNA/NRY pools of European Americans: they have less than 7% mtDNAs and less than 2% NRYs from non-European sources. Additionally, there is <2% Native American contribution to Philadelphian African American ancestry and the admixture from combined mtDNA/NRY estimates is consistent with the admixture derived from autosomal genetic data. To further dissect these estimates, we have analyzed our samples in the context of different demographic groups in the Americas.

Conclusions

We found that sex-biased admixture in African-derived populations is present throughout the Americas, with continual influence of European males, while Native American females contribute mainly to populations of the Caribbean and South America. The high non-European female contribution to the pool of European-derived populations is consistently characteristic of Iberian colonization. These data suggest that genomic data correlate well with historical records of colonization in the Americas.     

Assessing population genetic structure of sorghum landraces from North-western Morocco using allozyme and microsatellite markers

 The level of genetic diversity and the population genetic structure of sorghum landraces from North-western Morocco have been investigated based on direct field-sampling using both allozyme and microsatellite markers. As expected, microsatellite markers showed a much higher degree of polymorphism than allozymes, but relative measures of genetic structure such as Wright’s inbreeding coefficient F _IS and Nei’s coefficient of genetic differentiation G _ST were similar for the two sets of markers. Substantial inbreeding was found to occur within fields, which confirms that sorghum is predominantly selfing under cultivation. Most of the genetic diversity in Moroccan landraces occurs within fields (more than 85%), as opposed to among fields or among regions, a result which contrasts to those of studies based on accessions from germplasm collections. It is suggested that individual fields of sorghum constitute valuable units of conservation in the context of in situ conservation practices. Received: 8 December 1998 / Accepted: 28 December 1998     

Genome-wide analysis indicates more Asian than Melanesian ancestry of Polynesians

Analyses of mitochondrial DNA (mtDNA) and nonrecombining Y chromosome (NRY) variation in the same populations are sometimes concordant but sometimes discordant. Perhaps the most dramatic example known of the latter concerns Polynesians, in which about 94% of Polynesian mtDNAs are of East Asian origin, while about 66% of Polynesian Y chromosomes are of Melanesian origin. Here we analyze on a genome-wide scale, to our knowledge for the first time, the origins of the autosomal gene pool of Polynesians by screening 377 autosomal short tandem repeat (STR) loci in 47 Pacific Islanders and compare the results with those obtained from 44 Chinese and 24 individuals from Papua New Guinea. Our data indicate that on average about 79% of the Polynesian autosomal gene pool is of East Asian origin and 21% is of Melanesian origin. The genetic data thus suggest a dual origin of Polynesians with a high East Asian but also considerable Melanesian component, reflecting sex-biased admixture in Polynesian history in agreement with the Slow Boat model. More generally, these results also demonstrate that conclusions based solely on uniparental markers, which are frequently used in population history studies, may not accurately reflect the history of the autosomal gene pool of a population.     

Organisation of the variability of abundant proteins in seven geographical origins of maritime pine (Pinus pinaster Ait.)

The comparison of 42 two-dimensional protein patterns from megagametophytes of maritime pine from seven geographical origins enabled the analysis of the genetic variability of abundant proteins. More than 84% of the polypeptides were variable. The intra- and inter-origin variability levels were of a similar magnitude. Correspondence analysis and a dendrogram computed using a dissimilarity index between individuals showed three main groups. The first group included the individuals from Landes (France), Portugal, eastern Spain, and Corsica, without individualising the provenances. The second group was composed of accessions from Italy and Sardinia, and the individuals of each location were separated. The third group included all of the individuals of Moroccan origin. This clustering was in agreement with the Atlantic, Mediterranean and North African structuration of maritime pine established from terpene data.     

Mitochondrial DNA variation in Moroccan and Spanish honey bee populations

The mitochondrial DNAs of 192 Moroccan and 173 Spanish honey bee colonies were characterized by a rapid test involving the restriction by DraI of a PCR-fragment of the COI-COII region. In Morocco, we found eight haplotypes, all characteristic of the African (A) lineage, suggesting that most if not all the maternal lineages of the colonies repeatedly imported from Europe over the last 150 years have not contributed mitochondrial genomes to the local population. Using two new genetic distances analogous to the shared allele distance defined for nuclear genes, we showed that Morocco was most probably colonized by two sublineages, one from the north-east and the other one from the south of the country and that the contact zone between them extends along both sides of the Atlas range. In Spain, we found eight haplotypes characteristic of lineage A (six in common with Morocco) and four of lineage M (the West European lineage). The distribution of haplotypes of both lineages forms a gradient with c. 10% of lineage M in the south of Spain (Seville) and up to 100% in the north (San Sebastian). Three hypotheses are presented to explain the large differences of haplotype frequencies between Moroccan and lineage A Spanish colonies: a non-Moroccan origin of lineage A in Spain, an ancient Moroccan origin or a recent Moroccan origin with a rapid shift of haplotype frequencies due to a founder effect.     

Hares in Corsica: high prevalence of <Emphasis Type="Italic">Lepus corsicanus</Emphasis> and hybridization with introduced <Emphasis Type="Italic">L. europaeus</Emphasis> and <Emphasis Type="Italic">L. granatensis</Emphasis>

The Italian hare, Lepus corsicanus, was first described in Corsica more than 100 years ago, but the knowledge on the status of the species in this island remains scarce. Moreover, frequent introductions of thousands of individuals from other hare species, namely Lepus europaeus and Lepus granatensis, into Corsica are known to have occurred and an updated assessment of the prevalence of L. corsicanus in Corsica is therefore of utmost importance. Here, to estimate the relative prevalence of the hare species present in Corsica, we conducted a molecular analysis on 67 samples collected by hunters between 2002 and 2007 in 36 Corsican communes. Sequencing of portions of the nuclear gene transferrin and of the control region of the mitochondrial DNA allowed classifying most of the collected samples as belonging to L. corsicanus (70.1%). Of the sampled Corsican communes, 86.1% contained this species, while only in 11.1%, L. europaeus was present. Three of the analyzed specimens showed an inconsistent molecular assignment between markers suggesting a hybrid origin: L. corsicanus × L. europaeus, L. corsicanus × L. granatensis, and L. europaeus × L. granatensis. The first two cases of hybridization had never been described in nature, even in studies focusing on hares from Italy where L. corsicanus and L. europaeus are often sympatric. These results stress the real risk of corrosion of the native gene pool of L. corsicanus via hybridization with introduced species. We highlight the need of urgently rethinking the management plan of hare populations in Corsica.     

Patterns of nuclear and mitochondrial DNA variation in Iberian populations of <Emphasis Type="Italic">Emys orbicularis</Emphasis> (Emydidae): conservation implications

The European pond turtle (Emys orbicularis) is threatened and in decline in several regions of its natural range, due to habitat loss combined with population fragmentation. In this work, we have focused our efforts on studying the genetic diversity and structure of Iberian populations with a fine-scale sampling (254 turtles in 10 populations) and a representation from North Africa and Balearic island populations. Using both nuclear and mitochondrial markers (seven microsatellites, ∼1048 bp nDNA and ∼1500 bp mtDNA) we have carried out phylogenetic and demographic analyses. Our results show low values of genetic diversity at the mitochondrial level although our microsatellite dataset revealed relatively high levels of genetic variability with a latitudinal genetic trend decreasing from southern to northern populations. A moderate degree of genetic differentiation was estimated for Iberian populations (genetic distances, F _ST values and clusters in the Bayesian analysis). The results in this study combining mtDNA and nDNA, provide the most comprehensive population genetic data for E. orbicularis in the Iberian Peninsula. Our results suggest that Iberian populations within the Iberian–Moroccan lineage should be considered as a single subspecies with five management units, and emphasize the importance of habitat management rather than population reinforcement (i.e. captive breeding and reintroduction) in this long-lived species.     

Early Holocenic and Historic mtDNA African Signatures in the Iberian Peninsula: The Andalusian Region as a Paradigm

Determining the timing, identity and direction of migrations in the Mediterranean Basin, the role of “migratory routes” in and among regions of Africa, Europe and Asia, and the effects of sex-specific behaviors of population movements have important implications for our understanding of the present human genetic diversity. A crucial component of the Mediterranean world is its westernmost region. Clear features of transcontinental ancient contacts between North African and Iberian populations surrounding the maritime region of Gibraltar Strait have been identified from archeological data. The attempt to discern origin and dates of migration between close geographically related regions has been a challenge in the field of uniparental-based population genetics. Mitochondrial DNA (mtDNA) studies have been focused on surveying the H1, H3 and V lineages when trying to ascertain north-south migrations, and U6 and L in the opposite direction, assuming that those lineages are good proxies for the ancestry of each side of the Mediterranean. To this end, in the present work we have screened entire mtDNA sequences belonging to U6, M1 and L haplogroups in Andalusians—from Huelva and Granada provinces—and Moroccan Berbers. We present here pioneer data and interpretations on the role of NW Africa and the Iberian Peninsula regarding the time of origin, number of founders and expansion directions of these specific markers. The estimated entrance of the North African U6 lineages into Iberia at 10 ky correlates well with other L African clades, indicating that U6 and some L lineages moved together from Africa to Iberia in the Early Holocene. Still, founder analysis highlights that the high sharing of lineages between North Africa and Iberia results from a complex process continued through time, impairing simplistic interpretations. In particular, our work supports the existence of an ancient, frequently denied, bridge connecting the Maghreb and Andalusia.     

Genetic diversity in the mtDNA control region and population structure in the small yellow croaker <Emphasis Type="Italic">Larimichthys polyactis</Emphasis>

The genetic diversity and population genetic structure of the small yellow croaker (Larimichthys polyactis) were investigated. One hundred and fourteen individuals were sampled from 8 localities of the Yellow Sea and the northern East China Sea. Genetic variation in DNA sequences were examined from the first hypervariable region (HVR-1) of the mitochondrial DNA control region. High levels of haplotype diversity (h = 0.98 ± 0.87%) in the HVR-1 region were detected, indicating a high level of genetic diverstiy. A total of 84 polymorphic sites were found, and 87 haplotypes were defined. The pairwise nucleotide differences between samples ranged from 3.83 ± 2.19 to 6.56 ± 3.25. The demographic history of L. polyactis was examined by using neutrality tests and mismatch distribution analysis, which indicated a Pleistocene population expansion at about 49,300–197,000 years. The star burst structure of the minimum spanning tree also suggestted a very recent origin for most haplotypes. Hierarchical molecular variance analysis (AMOVA) and conventional population Fst comparisons revealed no significant genetic structure throughout the examined range, which is inconsistent with previous findings based on the morphological and ecological studies. Long-term dispersal and high gene flow likely have contributed to the genetically homogeneous population structure of the species. The knowledge on genetic diversity and genetic structure will be crucial to establish appropriate fishery management stocks for the species.