Contrasting spatial genetic structure in Annona crassiflora populations from fragmented and pristine savannas

In continuous populations, fine-scale genetic structure tends to be stronger in species with restricted pollen and seed dispersal. However, habitat fragmentation and disturbances can affect genetic diversity and spatial genetic structure due to disruption in ecological processes, such as plant reproduction and seed dispersal. In this study, we compared the genetic diversity and fine-scale spatial genetic structure (SGS) in two populations of Annona crassiflora (Annonaceae) in a pristine savanna Reserve (ESECAE) and in a fragmented disturbed savanna area (PABE), both in Cerrado biome in Central Brazil. The analyses were based on the polymorphism at 10 microsatellite loci. Our working hypothesis was that SGS is stronger and genetic diversity is lower in population at fragmented area (PABE) than at pristine area (ESECAE). Both populations presented high levels of polymorphism and genetic diversity and showed no sign of bottleneck for both Wilcoxon sign-rank test for heterozygosity excess (p > 0.05) and coalescent analyses (growth parameter g not different from zero), but population at fragmented area showed higher fixation index and stronger SGS. Besides, populations are significantly differentiated (F _ST = 0.239, R _ST = 0.483, p < 0.001 for both). Coalescent analyses showed high historical effective population sizes for both populations, high gene flow between ESECAE and PABE and recent time to most recent common ancestor (~37 k year BP). Our results suggest that despite the high genetic diversity, fragmentation and disturbance may have been affecting populations of this species increasing mating between closely related individuals leading to high fixation index and strong SGS.     

Conservation genetics of the annual hemiparasitic plant <Emphasis Type="Italic">Melampyrum sylvaticum</Emphasis> (Orobanchaceae) in the UK and Scandinavia

Melampyrum sylvaticum is an endangered annual hemiparasitic plant that is found in only 19 small and isolated populations in the United Kingdom (UK). To evaluate the genetic consequences of this patchy distribution we compared levels of diversity, inbreeding and differentiation from ten populations from the UK with eight relatively large populations from Sweden and Norway where the species is more continuously distributed. We demonstrate that in both the UK and Scandinavia, the species is highly inbreeding (global F _IS = 0.899). Levels of population differentiation were high (F’_ST = 0.892) and significantly higher amongst UK populations (F’_ST = 0.949) than Scandinavian populations (F’_ST = 0.762; P < 0.01). The isolated populations in the UK have, on average, lower genetic diversity (allelic richness, proportion of loci that are polymorphic, gene diversity) than Scandinavian populations, and this diversity difference is associated with the smaller census size and population area of UK populations. From a conservation perspective, the naturally inbreeding nature of the species may buffer the species against immediate effects of inbreeding depression, but the markedly lower levels of genetic diversity in UK populations may represent a genetic constraint to evolutionary change. In addition, the high levels of population differentiation suggest that gene flow among populations will not be effective at replenishing lost variation. We thus recommend supporting in situ conservation management with ex situ populations and human-mediated seed dispersal among selected populations in the UK.     

Cryptic genetic subdivision in the San Benito evening primrose (Camissonia benitensis)

When rare plants are distributed across a range of habitats, ecotypic differentiation may arise requiring customized conservation measures. The rate of local adaptation may be accelerated in complex landscapes with numerous physical barriers to gene flow. In such cases, examining the distribution of genetic diversity is essential in determining conservation management units. We investigated the distribution of genetic diversity in the federally threatened Camissonia benitensis (Onagraceae), which grows in two distinct serpentine habitats across several watersheds in San Benito, Fresno, and Monterey Cos., CA, USA. We compared genetic diversity with that of its two widespread relatives, C. contorta and C. strigulosa, and examined the potential for hybridization with the latter species. Genotyping results using seven heterospecific microsatellite markers indicate that differentiation between habitat types was weak (F _ST = 0.0433) and in an AMOVA analysis, there was no significant partitioning of molecular variation between habitats. Watersheds accounted for 11.6 % of the molecular variation (pairwise F _ST = 0.1823–0.4275). Three cryptic genetic clusters were identified by InStruct and STRUCTURE that do not correlate with habitat or watershed. C. benitensis exhibits 5–11× higher inbreeding levels and 0.54× lower genetic diversity in comparison to its close relatives. We found no evidence of hybridization between C. benitensis and C. strigulosa. To maximize conservation of the limited amount of genetic diversity in C. benitensis, we recommend mixing seed representing the three cryptic genetic clusters across the species’ geographic range when establishing new populations.     

Genetic variation and differentiation in Juniperus excelsa M. Bieb. populations in Turkey

Genetic variation within and among six populations of Juniperus excelsa M. Bieb., in a common garden in Lakes District of Turkey, was analyzed using four nuclear microsatellite primer pairs originally developed for J. communis. A total of five loci were observed as Jc037 amplified two distinct size ranges. The number of alleles observed for the species varied from 2 to 13, with an average of 4.5 alleles per locus. The mean expected heterozygosity (H _e) of populations was 0.584, after correction for null alleles. The mean F _IS value (?0.014) was close to zero showing no significant deviation from Hardy–Weinberg equilibrium. A low level of genetic differentiation was observed among populations (F _ST = 0.028; p < 0.001) and Nei’s genetic distance ranged from 0.014 to 0.120 between population pairs. Furthermore, there was no significant correlation between genetic distances on the one hand and geographic distances and trait differentiation on the other hand. However, the eastern populations Bey?ehir and Sorgun showed very similar genotypic structures and were differentiated from all other populations. A continuous monitoring of phenotypic traits and the association between nucleotide variation in functional genes and adaptive traits such as drought and frost tolerance of J. excelsa populations in common gardens will be useful to design effective conservation strategies in the future.     

Genetic Differentiation of Colombian Populations of <Emphasis Type="Italic">Anopheles darlingi</Emphasis> Root (Diptera: Culicidae)

Anopheles darlingi Root is a primary vector of malaria in the neotropic region, a species not just highly anthropophilic but very efficient in transmitting Plasmodium species and considered the most important vector in the Amazon region. The main goal of this study was to determine the genetic structure of the A. darlingi populations using microsatellites (STR) in western and eastern regions of Colombia. DNA extraction was done with the cited protocol of band using the Genomic Prep? cell and tissue isolation commercial kits. We used the STR reported by Conn et al (Mol Ecol Notes 1: 223-225, 2001). The analysis with STR proved there was a high genetic diversity and significant alterations of the Hardy-Weinberg equilibrium. The greatest genetic diversity was recorded in Mitu (Vaupes) (Na = 14, Ho = 0.520). The lowest was in Pueblo Nuevo (Cordoba) (Na = 12, Ho = 0.457). The eastern region and the Mitu (Vaupes) populations presented the highest number of primer alleles (Ap = 30; Ap = 13; Ap = 9), with variations between 0.010 and 0.097. The AMOVA revealed that the whole population underwent moderate genetic differentiation (F _ST = 0.063, p < 0.05). The same differentiation was noticed (0.06 < F _ST > 0.06, p < 0.05) with five of the six populations included in this job, and there was a low differentiation in the Las Margaritas (Santander) area (F _ST = 0.02s3, p < 0.05). Our results suggest a slight positive correlation, which does not show a statistical significance between the geographic and genetic distances, probably suggesting that the moderate genetic differentiation found between pairs of populations does not need to be explained for the hypothesis of separation by distance.     

Genetic Diversity and Geographic Differentiation of the Giant Tiger Shrimp (Penaeus monodon) in Thailand Analyzed by Mitochondrial COI Sequences

Genetic diversity and geographic differentiation of the giant tiger shrimp, Penaeus monodon, in Thai waters (Satun, Trang, Phangnga, and Ranong in the Andaman Sea and Chumphon and Trat in the Gulf of Thailand) were examined by COI polymorphism (N = 128). We observed 28 COI mitotypes across all investigated individuals. The sequence divergence between pairs of mitotypes was 0.00–20.76%. A neighbor-joining tree clearly indicated lineage separation of Thai P. monodon and large nucleotide divergence between interlineage mitotypes but limited divergence between intralineage mitotypes. High genetic diversity was found (mean sequence divergence = 6.604%, haplotype diversity = 0.716–0.927, π = 2.936–8.532%). F-statistics (F _ST) and an analysis of molecular variance (AMOVA) indicated that the gene pool of Thai P. monodon was not homogeneous but genetically differentiated intraspecifically (P < 0.05). Six samples of P. monodon could be allocated into three different genetic populations: Trat (A), Chumphon (B), and the Andaman samples Satun, Trang, Phangnga, and Ranong (C). Contradictory results regarding patterns of geographic differentiation previously reported by various molecular approaches were clarified by this study.     

Genetic diversity of the endangered Chinese endemic herb Saruma henryi Oliv. (Aristolochiaceae) and its implications for conservation

Saruma henryi Oliv., the only representative of the monotypic genus Saruma Oliv. (Aristolochiaceae), is an endangered perennial herb endemic to China. It is a phylogenetically, ecologically, and medicinally important species. In the present study, inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 14 populations. A total of 16 selected primers yielded 175 bright and discernible bands, with an average of 10.94 per primer. POPGENE analysis showed that the genetic diversity was quite low at the population level (h = 0.0447–0.1243; I = 0.0642–0.1853; PPB = 10.29–36.57%), but pretty high at the species level (h = 0.2603; I = 0.3857; PPB = 73.71%). The hierarchical analysis of molecular variance (AMOVA) revealed a high level of genetic differentiation among populations (67.18% of total variance components, P < 0.001), in line with the gene differentiation coefficient (G _ST = 0.6903) and the limited among-population gene flow (N _m = 0.2243). Both Principal Coordinates Analysis (PCoA) and UPGMA cluster analysis supported the grouping of all 14 populations into three geographic groups, among which there occurred a moderate level of genetic differentiation (33.18% of total variance components, P < 0.001) as shown by AMOVA analysis. In addition, Mantel test revealed a significant correlation between genetic and geographic distances among populations (r = 0.7792, P = 0.001), indicating the role of geographic isolation in shaping its present population genetic structure. The present levels and patterns of genetic diversity of S. henryi were assumed to result largely from its breeding system, geographic isolation, clonal growth, its unique biological traits and evolutionary history. The high genetic differentiation among populations implies that the conservation efforts should aim to preserve all the extant populations of this endangered herb.     

Genetic analysis of Pongamia pinnata (L.) Pierre populations using AFLP markers

A study of genetic diversity in Pongamia pinnata representing 33 candidate plus trees (CPT) was undertaken in five agro-ecological zones of Southern Peninsular India. Eleven primer combinations generated 532 bands with an average of 48 bands per primer combination. E-ACG/M-GCC showed the highest polymorphism of 98.80 %. E-ACG/M-GCC, E-CAA/M-CTG, and E-CAG/M-GTG with higher polymorphic information, marker index, and resolving power were found to be effective in detecting unique bands. Nei's gene diversity and Shannon's indices of 0.159 and 0.247, respectively, indicated the presence of high gene diversity in southern dry and transition zones of Karnataka. The inter-population differentiation between zones (G _ST) was 0.296. The level of gene flow (Nm) estimated was 1.34. Analysis of molecular variance indicated that 44.78 % of variance occurred within the provenance when compared to variations among agro-ecological zones (22.22 %) and among provenances within zones (33 %). Based on un-weighted pair group method using arithmetic averages method, the pongamia accessions were grouped into three major clusters and four sub-groups depending on their geographical locations. The diverse CPT identified in this study could be selected and used for tree breeding, germplasm conservation, and biofuel program in India and other tropical countries.     

Genetic structure and diversity in relation to the recently reduced population size of the rare conifer, <Emphasis Type="Italic">Pseudotsuga japonica</Emphasis>, endemic to Japan

Rare species consisting of small populations are subject to random genetic drift, which reduces genetic diversity. Thus, determining the relationship between population size and genetic diversity would provide key information for planning a conservation strategy for rare species. We used six microsatellite markers to investigate seven extant populations of the rare conifer Pseudotsuga japonica, which is endemic to the Kii Peninsula and Shikoku Island regions that are geographically separated by the Kii Channel in southwest Japan. The population differentiation of P. japonica was relatively high (F_ST = 0.101) for a coniferous species, suggesting limited gene flow among populations. As expected, significant regional differentiation (AMOVA; p?<?0.05) indicated genetic divergence across the Kii Channel. A strong positive correlation between census population size and the number of rare alleles (r?=?0.862, p?<?0.05) was found, but correlations with major indices of genetic diversity were not significant (allelic richness: r?=?0.649, p?=?0.104, expected heterozygosity: r?=?0.361, p?=?0.426). The observed order of magnitude of correlation with three genetic diversity indices corresponded with the theoretically expected order of each index’ sensitivity (i.e., the rate of decline per generation) to the bottleneck event. Thus, features that exhibit a faster response, i.e., the number of rare alleles, would have been subject to deleterious effects of the recent decline in population size, which is presumably caused by the development of extensive artificial plantations of other tree species over the last several decades. Finally, we propose a conservation plan for P. japonica based on our findings.     

Population stock structure of leatherback turtles (Dermochelys coriacea) in the Atlantic revealed using mtDNA and microsatellite markers

This study presents a comprehensive genetic analysis of stock structure for leatherback turtles (Dermochelys coriacea), combining 17 microsatellite loci and 763 bp of the mtDNA control region. Recently discovered eastern Atlantic nesting populations of this critically endangered species were absent in a previous survey that found little ocean-wide mtDNA variation. We added rookeries in West Africa and Brazil and generated longer sequences for previously analyzed samples. A total of 1,417 individuals were sampled from nine nesting sites in the Atlantic and SW Indian Ocean. We detected additional mtDNA variation with the longer sequences, identifying ten polymorphic sites that resolved a total of ten haplotypes, including three new variants of haplotypes previously described by shorter sequences. Population differentiation was substantial between all but two adjacent rookery pairs, and F _ST values ranged from 0.034 to 0.676 and 0.004 to 0.205 for mtDNA and microsatellite data respectively, suggesting that male-mediated gene flow is not as widespread as previously assumed. We detected weak (F _ST = 0.008 and 0.006) but significant differentiation with microsatellites between the two population pairs that were indistinguishable with mtDNA data. POWSIM analysis showed that our mtDNA marker had very low statistical power to detect weak structure (F _ST < 0.005), while our microsatellite marker array had high power. We conclude that the weak differentiation detected with microsatellites reflects a fine scale level of demographic independence that warrants recognition, and that all nine of the nesting colonies should be considered as demographically independent populations for conservation. Our findings illustrate the importance of evaluating the power of specific genetic markers to detect structure in order to correctly identify the appropriate population units to conserve.     

Population structure and genetic diversity of Stipa grandis P. Smirn,a dominant species in the typical steppe of northern China

Random amplified polymorphic DNA (RAPD) markers were used to characterize genetic heterogeneity within and among five populations of Stipa grandis in the Xilingol Plateau. Estimates of the percentage of polymorphic bands, Shannon's diversity information index and Nei's gene diversity index were comparatively high in the five populations, and the Population GSM was found to have the highest genetic diversity among all populations. An analysis of molecular variance indicated that the majority of variation existed within populations (74.12%), and that there was significant differentiation among populations (Φ_ST = 25.88%, P < 0.001). Genetic distance (Φ_ST) ranged from 0.198 to 0.310 and the differentiation between pair-wise populations was significant when individual pairs of populations were compared. Based on the Φ_ST values, gene flow (Nm) was estimated and was found to vary from 0.556 to 1.013 between pair-wise populations and 0.7412 among populations. The results of UPGMA cluster analysis and nonmetric multi-dimensional scaling analysis indicated that most variation occurred within populations and that genetic differentiation had happened between populations. These findings are important for a better understanding of the adaptive strategy of S. grandis in northern China and will be useful for conservation managers to work out an effective strategy to protect this important species.     

Plaque Image Characteristics, Hyperhomocysteinemia, and Gene Polymorphism of Homocysteine Metabolism-Related Enzyme (MTHFR C677T) in Acute Coronary Syndrome

This study aims to investigate the correlation between the different characteristics of plaques, plasma level of homocysteine (Hcy), and gene polymorphism of Hcy metabolism-related enzyme. In this consecutive case–control study, we measured the plasma Hcy level using fluorescence biochemistry method and examined the gene polymorphism of Hcy metabolism-related enzyme methylenetetrahydrofolate reductase (MTHFR) C677T using TaqMan probe technology. We also examined these using intravascular ultrasound. We studied the characteristics of the plaque, measured the cross-sectional areas of the external elastic membrane and the lumen, calculated the plaque area, plaque burden, and eccentricity index, and examined the remodeling index. Hard plaques were more dominant in the (SPA) group, whereas soft plaques were more dominant in the acute coronary syndrome (ACS) group (P < 0.001). The risk of plaque rupture and thrombus is higher in the ACS group (P < 0.05). Compared with SPA group, plaque burden was heavier in the ACS group (P < 0.05), but the eccentricity index is significantly higher in SPA group than in the ACS group (P < 0.001). Positive remodeling was more frequent in ACS group, whereas negative remodeling was more frequent in the SPA group (P < 0.001). Plasma Hcy levels were higher in the unstable than in the stable plaque group (P < 0.001). The constituent ratio of MTHFR C677T genotype were different in stable plaque group and vulnerable plaque group (P < 0.05). The T genotype can increase the incidence rate of vulnerable plaque. Hcy and MTHFR C677T gene polymorphism were found to be risk factors for vulnerable plaque. Therefore, these can be used as indices to predict the instability of atherosclerotic plaque.     

Genetic structure in the paleoendemic and endangered Petagnaea gussonei (Spreng.) Rauschert (Saniculoideae, Apiaceae) and implications for its conservation

Our investigation aims to understand the genetic structure and evolutionary history of Petagnaea gussonei, an ancient and endangered species belonging to the Saniculoideae subfamily (Apiaceae). It is paleoendemic to Sicily, with a small number of populations in the Nebrodi Mountains. A total of seven chloroplast microsatellite repeat loci and 12 AFLP primer combinations were used to screen 115 individuals corresponding to 17 populations. The ratio of seed to pollen flow was also calculated using the modified Ennos equation. A relatively high level of genetic diversity was detected with AFLPs (e.g., 0.045 < H < 0.278), and a moderate variation was also found using cpSSRs (0 < Hk < 0.667). Two different haplotypes (B and W) were identified, with five populations being monomorphic for haplotype B. There was no genetic differentiation on the basis of haplotypic frequency (G _ST) and similarity (R _ST), and no phylogeographic structure was detected among the populations. AFLP values also confirmed that the populations are not very genetically differentiated. The principal component analysis based on pairwise genetic differences showed three groupings without a geographical correlation. The AMOVA analysis indicates that the amount of variation is higher within populations (82 %) than among populations (18 %). Results of the pollen flow/seed flow ratio indicated positive values for each population, indicating that gene flow by seed is not more efficient than by pollen. Instead, the total pollen/seed flow for all population presents a negative value, suggesting that pollen dispersal does not appear to be more effective over the long range for gene flow than seed dispersal. This differentiation level supports the hypothesis that the fragmentation and isolation of the residual populations is in progress. This phenomenon is due not only to post-ice age climate changes, but also to direct and indirect anthropic actions.     

Insights into the biodiversity of the Succulent Karoo hotspot of South Africa: the population genetics of a rare and endemic halictid bee,Patellapis doleritica

Population genetic analyses are especially relevant for species considered threatened or highly endemic and for which other forms of biological information are lacking. Patellapis doleritica is a recently described communally nesting halictid bee of conservation concern because it is rare and endemic to the Succulent Karoo of South Africa. Moreover, its dispersal is considered to be restricted by its specialised nesting requirements and inclement weather conditions during its limited annual flight period, traits which may be common to other bee species of the region. We hypothesised that gene flow in P. doleritica was low, leading to marked genetic differentiation. Using 7 microsatellites, we investigated its mating and population genetic structure in 258 individuals (171 females and 87 males) from 7 populations spanning most of its known range. Deviation from Hardy–Weinberg equilibrium (F_IS = + 0.254) suggested P. doleritica to be inbred, as in many other communal nesting bee species. Global F_ST (0.028) and global G′_ST (0.216) revealed modest but significant differentiation between most populations, even across the very limited range of the species (ca. 25 km), with one genetically extreme outlier population. Despite inbreeding, we detected a surprisingly low frequency of diploid males (2 %). Patellapis doleritica nevertheless deserves special conservation attention since it is an endemic species with a low overall abundance and therefore possibly prone to environmental change and local extinction.     

Remarkably low genetic diversity and strong population structure in common bottlenose dolphins (Tursiops truncatus) from coastal waters of the Southwestern Atlantic Ocean

Knowledge about the ecology of bottlenose dolphins in the Southwestern Atlantic Ocean is scarce. Increased by-catch rates over the last decade in coastal waters of southern Brazil have raised concerns about the decline in abundance of local dolphin communities. Lack of relevant data, including information on population structure and connectivity, have hampered an assessment of the conservation status of bottlenose dolphin communities in this region. Here we combined analyses of 16 microsatellite loci and mitochondrial DNA (mtDNA) control region sequences to investigate genetic diversity, structure and connectivity in 124 biopsy samples collected over six communities of photographically identified coastal bottlenose dolphins in southern Brazil, Uruguay and central Argentina. Levels of nuclear genetic diversity were remarkably low (mean values of allelic diversity and heterozygosity across all loci were 3.6 and 0.21, respectively), a result that possibly reflects the small size of local dolphin communities. On a broad geographical scale, strong and significant genetic differentiation was found between bottlenose dolphins from southern Brazil–Uruguay (SB–U) and Bahía San Antonio (BSA), Argentina (AMOVA mtDNA Φ_ST = 0.43; nuclear F_ST = 0.46), with negligible contemporary gene flow detected based on Bayesian estimates. On a finer scale, moderate but significant differentiation (AMOVA mtDNA Φ_ST = 0.29; nuclear F_ST = 0.13) and asymmetric gene flow was detected between five neighbouring communities in SB–U. Based on the results we propose that BSA and SB–U represent two distinct evolutionarily significant units, and that communities from SB–U comprise five distinct Management Units (MUs). Under this scenario, conservation efforts should prioritize the areas in southern Brazil where dolphins from three MUs overlap in their home ranges and where by-catch rates are reportedly higher.     

Evidence for genetic differentiation among Caspian tern (Hydroprogne caspia) populations in North America

The Caspian tern (Hydroprogne caspia) is a globally distributed seabird that breeds throughout North America, generally in low numbers. Many colonies are threatened by habitat loss and pollution. Additionally, adult terns compete directly with salmonid stocking programs on the west coast, where a large proportion of the fish they feed their young are stocked salmon smolts. North America colonies have been classified into five ‘breeding groups’ based on banding data and geography. To help delineate effective management units, we characterized variation in mitochondrial DNA (488 base pair fragment of cytochrome b) and five microsatellite loci among 111 terns from six sites representing three of the North American breeding areas. We found significant range-wide population differentiation (cytochrome b: global Φ_ST = 0.12, P < 0.01; microsatellites: global F_ST = 0.094, P < 0.001). Pacific Coast sites differed genetically from sites east of the Rocky Mountains, and sites in Central Canada differed from those in the Great Lakes region. Gene flow among these three regions appears to be restricted. Thus, our results indicate that at least three of the breeding regions delineated using banding data and geography should be treated as separate management units.     

Population genetic structure of wild daffodils (Narcissus pseudonarcissus L.) at different spatial scales

We studied the population genetic and clonal structure of the endangered long-lived perennial plant Narcissus pseudonarcissus using random amplified polymorphic markers. Estimates for mean gene diversity within 15 populations of N. pseudonarcissus of three neighbouring geographical regions were high in comparison to other long-lived perennials (H _eN = 0.33). The genetic diversity of the two smallest populations (<200 plants) was significantly reduced, indicating loss of genetic variability due to drift. The analysis of the population genetic structure revealed a significant genetic differentiation both between regions (Φ_ST = 0.06) and between populations within regions (Φ_ST = 0.20). However, there was incomplete correspondence between geographical regions and the population genetic structure. In order to preserve the overall genetic variation in wild populations of N. pseudonarcissus, management measures should thus aim to protect many populations in each region. The spatial genetic structure within populations of N. pseudonarcissus was in agreement with an isolation by distance model indicating limited gene flow due to pollinator behaviour and restricted seed dispersal. The very restricted spatial extent of clonal growth (<5 cm) and the high level of clonal diversity indicate that clonal growth in N. pseudonarcissus is not an important mode of propagation and that management measures should favour sexual reproduction in order to avoid further reductions in the size and number of populations.     

Population structure and conservation implications for the loggerhead sea turtle of the Cape Verde Islands

The Cape Verde Islands harbour the second largest nesting aggregation of the globally endangered loggerhead sea turtle in the Atlantic. To characterize the unknown genetic structure, connectivity, and demographic history of this population, we sequenced a segment of the mitochondrial (mt) DNA control region (380 bp, n = 186) and genotyped 12 microsatellite loci (n = 128) in females nesting at three islands of Cape Verde. No genetic differentiation in either haplotype or allele frequencies was found among the islands (mtDNA F _ST = 0.001, P > 0.02; nDNA F _ST = 0.001, P > 0.126). However, population pairwise comparisons of the mtDNA data revealed significant differences between Cape Verde and all previously sequenced Atlantic and Mediterranean rookeries (F _ST = 0.745; P < 0.000). Results of a mixed stock analysis of mtDNA data from 10 published oceanic feeding grounds showed that feeding grounds of the Madeira, Azores, and the Canary Islands, in the Atlantic Ocean, and Gimnesies, Pitiüses, and Andalusia, in the Mediterranean sea, are feeding grounds used by turtles born in Cape Verde, but that about 43% (±19%) of Cape Verde juveniles disperse to unknown areas. In a subset of samples (n = 145) we evaluated the utility of a longer segment (~760 bp) amplified by recently designed mtDNA control region primers for assessing the genetic structure of Atlantic loggerhead turtles. The analysis of the longer fragment revealed more variants overall than in the shorter segments. The genetic data presented here are likely to improve assignment and population genetic analyses, with significant conservation and research applications.