Geographic variation within a tandemly repeated mitochondrial DNA D-loop region of a North American freshwater fish, Pylodictis olivaris

The present study reports the distribution of a 35-bp mitochondrial DNA (mtDNA) D-loop tandemly repeated sequence in the populations of a North American freshwater catfish, Pylodictis olivaris, and the important role of a past geological event in the phylogeographic pattern of this species. A total of 330 individuals of flathead catfish, representing 34 drainages throughout the species' native range in the United States, were collected. While more than 70% of individuals sampled from the Southeastern Gulf Coast drainages were characterized by the presence of a 35-bp mtDNA D-loop tandem repeat proximal to the 5′ end, more than 95% of samples from the Mississippi River and its tributaries, as well as from the drainages of the Southwest Gulf Coast region, lack this tandem repeat. Concomitantly, phylogenetic analyses revealed the existence of two distinct matrilineal lineages (lineage I and II) of P. olivaris, which were estimated to have diverged from a common ancestor sometime between 0.70 and 2.05 myr ago. While one lineage is comprised of samples from the Mississippi River and its tributaries and rivers draining to the Southwest Gulf Coast, the other lineage is comprised of samples from the Southeastern Gulf Coast drainages. Each lineage also has two sub-lineages, which also showed geographic specificity.     

Mitochondrial DNA Diversity of Honey Bees (Apis mellifera) from Unmanaged Colonies and Swarms in the United States

To study the genetic diversity of honey bees (Apis mellifera L.) from unmanaged colonies in the United States, we sequenced a portion of the mitochondrial DNA COI–COII region. From the 530 to 1,230 bp amplicon, we observed 23 haplotypes from 247 samples collected from 12 states, representing three of the four A. mellifera lineages known to have been imported into the United States (C, M, and O). Six of the 13 C lineage haplotypes were not found in previous queen breeder studies in the United States. The O lineage accounted for 9% of unmanaged colonies which have not yet been reported in queen breeder studies. The M lineage accounted for a larger portion of unmanaged samples (7%) than queen breeder samples (3%). Based on our mitochondrial DNA data, the genetic diversity of unmanaged honey bees in the United States differs significantly from that of queen breeder populations (p < 0.00001). The detection of genetically distinct maternal lineages of unmanaged honey bees suggests that these haplotypes may have existed outside the managed honey bee population for a long period.     

Mitochondrial DNA phylogeography of the three-spined stickleback (Gasterosteus aculeatus) in Europe-evidence for multiple glacial refugia

An analysis of mitochondrial DNA sequence variation in 172 three-spined sticklebacks (Gasterosteus aculeatus) sampled across the European distribution range revealed three major evolutionary lineages occupying relatively large and separate geographic areas. The trans-Atlantic lineage comprised of populations spanning from the East Coast of USA to the continental Europe and was basal group to the other European lineages in the phylogeny. The European lineage included populations located in the Western and Eastern Europe, British Isles, Scandinavia as well as some parts of the Mediterranean region. The third lineage was specific to the Black Sea drainages. The within lineage structure was characterized by significant excess of low frequency haplotypes and star-like mtDNA genealogies, which suggest a recent population expansions to the formerly glaciated marine and freshwater environments. A coalescent-based method dated the splits between the major lineages to have occurred during the Saalian and Weichselian glaciations in the late Pleistocene, depending on the molecular clock calibration. The coalescent simulations further indicate high degree of genetic diversity within the lineages and a substantial increase in the genetic diversity in the European lineage relative to the ancestral level. In addition to the three major lineages, the freshwater populations in R. Neretva and L. Skadar in the Adriatic Sea coast region harboured unique and highly divergent haplotypes suggesting long independent histories of these populations. Evidence from mtDNA analyses suggests that these populations deserve a status of an evolutionary significant unit.     

Contrasting patterns of genetic diversity between the northern and southern populations of yellow bullhead catfish, Ameiurus natalis in North America

Environmental conditions have profound influence on the life history characteristics of a species, for instance, the yellow bullhead (Ameiurus natalis) population in its southernmost native range, South Florida was previously reported to be distinguished from other A. natalis populations in the United States by growth rates and feeding habits. Utilizing mitochondrial DNA control region sequence data, the present study sought to evaluate the patterns of intraspecific diversification of this North American freshwater catfish, A. natalis. The analyses have revealed the existence of four distinct matrilineal lineages (Mississippi, Gulf coast, Southeast Atlantic, and South Florida) with strong geographic specificity. Although all the lineages showed rapid demographic expansion, the South Florida lineage is shown to have greater genetic diversity than the remaining lineages. The persistence of more favorable environmental conditions and suitable habitats during the late-Pleistocene period in southern Florida could be the possible explanation for such genetic disparities among the lineages. However, taken together with the conclusion of previous studies, the present study predicted that the recurrent density-dependent process resulting from the altercation of hydrology in South Florida may cause the reduction in genetic diversity and put this species at risk in this region.     

Variability in triactinomyxon production from Tubifex tubifex populations from the same mitochondrial DNA lineage infected with Myxobolus cerebralis, the causative agent of whirling disease in salmonids

Myxobolus cerebralis, the causative agent of whirling disease, infects both salmonid fish and an aquatic oligochaete, Tubifex tubifex. Although M. cerebralis has been detected in river drainages throughout the United States, disease severity among wild fish populations has been highly variable. Tubifex tubifex populations have been genetically characterized using sequences from the 16S mitochondrial DNA (mtDNA) gene, the 18S ribosomal RNA gene, the internal transcribed spacer region 1 (ITS1), and randomly amplified polymorphic DNA (RAPD). Our earlier work indicated that large differences in compatibility between the parasite and populations of T. tubifex may play a substantial role in the distribution of whirling disease and resulting mortality in different watersheds. In the present study, we examined 4 laboratory populations of T. tubifex belonging to 16S mtDNA lineage III and 1 population belonging to 16S mtDNA lineage I for triactinomyxon (TAM) production after infection with M. cerebralis myxospores. All 4 16S mtDNA lineage III populations produced TAMs, but statistically significant differences in TAM production were observed. Most individuals in the 16S mtDNA lineage III-infected populations produced TAMs. The 16S mtDNA lineage I population produced few TAMs. Further genetic characterization of the 16S mtDNA lineage III populations with RAPD markers indicated that populations producing similar levels of TAMs had more genetic similarity.     

Subspecies and units for conservation and management of the northern bobwhite in the eastern United States

The northern bobwhite (Colinus virginianus) is a small game bird with sedentary lifestyle and has experienced population declines throughout most of its native distribution in the eastern United States. We investigated intraspecific genetic relationships among 14 local populations covering four putative subspecies (C. v. marilandicus, C. v. virginianus, C. v. mexicanus, and C. v. floridanus) in the United States. Analysis of mitochondrial DNA sequences revealed a small, but significant, genetic structure of northern bobwhite populations or subspecies in the eastern US. However, our results did not support current subspecies limits as distinct evolutionarily significant units, based on the amount of population genetic divergences and insufficient lineage sorting of mtDNA haplotypes among subspecies. Instead, our results suggest that C. v. virginianus, C. v. marilandicus, and C. v. mexicanus be merged into a single management unit, and C. v. floridanus be considered as another distinct unit for conservation and management.     

DIFFERING LEVELS OF AMONG-POPULATION DIVERGENCE IN THE MITOCHONDRIAL DNA OF PERIODICAL CICADAS RELATED TO HISTORICAL BIOGEOGRAPHY

Mitochondrial DNA (mtDNA) haplotypes were determined for 118 individuals of 13-and 17-year periodical cicadas (genus Magicicada) collected from 16 localities throughout the Midwest and eastern United States. Two distinct mtDNA lineages, identified as A and B, differ by 2.5% based on analysis of fragment patterns and restriction maps. Observed levels of mtDNA diversity within each lineage are low compared to estimates for other taxa. The two lineages are regionally segregated, with the boundary line occurring at a latitude of approximately 33° North. The levels of mtDNA diversity and population genetic structure differ within the two lineages. There is a remarkably low level of mean mtDNA divergence and no genetic structure in lineage A, whereas lineage B exhibits an order of magnitude higher level of mtDNA diversity and significant genetic structure among sampled populations. The low level of mtDNA diversity in cicadas may be attributed to (1) a population bottleneck that most likely occurred during the Pleistocene, (2) recent colonization following the retreat of the glaciers and the expansion of deciduous forests, and/or (3) high among-family reproductive variance (as a consequence of large population size, high fecundity, aggregative behavior of adults, and clumping of eggs). The difference in mtDNA diversity and population genetic structure between the lineages suggests that they experienced different biogeographic histories; we relate this to Pleistocene changes.     

Intraspecific phylogeography of the slender madtom: the complex evolutionary history of the Central Highlands of the United States

A number of different biogeographical studies of the Central Highlands of the United States have yielded conflicting area cladograms. We estimate the mtDNA phylogeny of populations of the slender madtom, Noturus exilis, a clear-water stream catfish. The goal is to compare population relationships to those reported in previous studies that used upland, stream-dwelling vertebrates. A region of the NADH dehydrogenase subunit 4 gene, along with adjacent tRNAs, was sequenced for population samples from 21 different Central Highlands rivers. Sequence difference among 39 haplotypes ranged from 0.1% to 4.8%. Most haplotypes were restricted to specific rivers and mapped well onto geography. Slender madtoms from different drainages contained mostly monophyletic groups of haplotypes genetically divergent from haplotypes found in other drainages, although a few haplotypes were found in well-separated drainages. The area cladogram for the slender madtom was not similar to any of the other cladograms for other species and species groups from the area. We discuss a variety of methodological and biological reasons for the discordance, and suggest that some of the discrepancies may be resolved by the sequencing of multiple genes per species. We recommend that more, and more extensive, intraspecific phylogeography studies should be conducted for species living in the Central Highlands rivers.     

Phylogeography of endemic ermine (Mustela erminea) in southeast Alaska

The North Pacific Coast (NPC) of North America is a region of high mammalian endemism, possibly due to its highly fragmented landscape and complex glacial history. For example, four island and one mainland subspecies of ermine, Mustela erminea, have been described as endemic to southeast Alaska alone. To better understand the role of past climatic change in generating diversity in the region, we examined DNA sequence variation in the mitochondrial cytochrome b gene of 210 ermine from across North America, with an emphasis on Alaska and British Columbia. We found three distinct (1.5-3.6% uncorrected 'p') lineages of ermine, all of which occur in southeast Alaska. One lineage includes a southeast Alaska endemic and specimens from Alaska (outside of southeast) and Eurasia. A second lineage includes two southeast Alaskan endemics and ermine from western Canada and the coterminous United States. The close relationships of these purported endemics to ermine outside of southeast Alaska suggest that they colonized the region from Beringian and southern glacial refugia, respectively, following deglaciation of the NPC. The third lineage appears restricted to the Prince of Wales Island complex in southeast Alaska (two subspecies) and Graham Island (Haida Gwaii), British Columbia. This restricted distribution suggests that these populations may be derived from relicts that persisted in a coastal refugium during the Wisconsin glaciation. Studies of nuclear genes and adaptive morphological evolution are necessary to further explore discrepancies between the geographical pattern of differentiation based on mtDNA and the existing subspecific taxonomy based on morphology.     

Phylogeographic study of brown trout from Serbia,based on mitochondrial DNA control region analysis

In order to illuminate the phylogeography of brown trout (Salmo trutta) populations in the Balkan state of Serbia, the 561 bp 5''-end of mtDNA control region of 101 individuals originating from upland tributaries of the Danubian, Aegean and Adriatic drainages were sequenced and compared to corresponding brown trout sequences obtained in previous studies. Among 15 haplotypes found, 14 were considered native, representing the Danubian and Adriatic lineages of the brown trout, while one haplotype (ATcs1), found only in two individuals originating from two stocked rivers, corresponded to the Atlantic lineage and was considered introduced. Native haplotypes exhibited a strong geographic pattern of distribution: the Danubian haplotypes were strictly confined to the Danubian drainage, while the Adriatic haplotypes dominated in the Aegean and Adriatic drainages; most of the total molecular variance (69%) was attributed to differences among the drainages. Phylogenetic reconstruction, supplemented with seven haplotypes newly described in this study, suggested a sister position of the Atlantic-Danubian and Adriatic-Mediterranean-marmoratus ("southern") phylogenetic group, and pointed to the existence of a distinct clade, detected within the "southern" group. The data obtained confirmed our expectation of the existence of high genetic diversity in Balkan trout populations, and we recommend more widespread surveys covering trout stocks from the region.     

Phylogeography of the flathead mullet Mugil cephalus in the north-west Pacific as inferred from the mtDNA control region

The population genetic structure and historical demography of the flathead mullet Mugil cephalus were investigated using the mtDNA control region (CR) sequences (909–1015 bp) of 126 individuals collected from seven locations in the north-west Pacific between 2005 and 2007. Haplotype diversity ( h = 0·9333–1·000) and nucleotide diversity (π = 0·0046–0·1467) varied greatly among the sampling locations. Phylogenetic analysis of the CR sequences indicated that M. cephalus in the north-west Pacific belongs to two highly divergent lineages (lineages 1 and 2), with the inferred population structure being closely associated with the distribution of both lineages. Two populations were identified, one from the East China Sea and the other from the South China Sea. The former samples were obtained from Taiwan and Qingdao of north China and associated with lineage 1 haplotypes. The latter samples were collected from the Philippines, Pearl River of South China and two samples from Japan, all of which were associated with lineage 2. Japanese samples from Okinawa and Yokosuka had different degrees of mixing between lineages 1 and 2. Historical demographic variables in both populations indicated that Pleistocene glaciations had a strong impact on M. cephalus in the north-west Pacific, resulting in a recent demographic decline of the East China Sea population but in demographic equilibrium for the South China Sea population. Japan appears to be a contact zone between lineages 1 and 2, but it may also be indicative of coexistence between resident and migratory populations. Further global studies are required to clarify the taxonomic status of this cosmopolitan species.     

Lack of mtDNA variation among remote middle Volga and upper Ural brown trout suggests recent and rapid recolonization

Brown trout populations from the middle Volga and upper Ural drainages in the Russian Federation were analyzed with respect to their inter‐relationships and phylogenetic status using complete mtDNA control region sequences and 10 microsatellite loci. Among 56 individuals from eight populations (six from the middle Volga and two from the upper Ural drainages) only one haplotype was detected: Iran1 from the Danube phylogenetic lineage. This haplotype is very frequent in the southern Caspian basin in Iran. Given the high diversity of haplotypes in northern Iran, in contrast to the complete domination of the Iran1 haplotype in our study, it seems likely that Iran1 reached the middle Volga and upper Ural drainages as a consequence of colonization from the southern Caspian basin. In contrast to the mtDNA analysis, a more pronounced differentiation was observed among the studied populations on the basis of microsatellite DNA data. Based on this result, it is proposed that each population should be treated as a distinct management unit in the context of future conservation activities.     

Genetic diversity of Garra rufa Heckel, 1843 (Teleostei: Cyprinidae) in Anatolia

In the present study, mitochondrial DNA polymerase chain reaction-restriction-fragment length polymorphism (PCR-RFLP) and nuclear DNA inter-simple sequence repeat (ISSR) assays were used to assess the phylogenetic and phylogeographic relationships among Garra rufa samples from Anatolia. The complete mtDNA NADH 3/4 dehydrogenase (ND-3/4) gene amplified by PCR was digested with eight restriction enzymes. These enzymes produced 20 composite haplotypes for G. rufa populations. All the mtDNA haplotypes detected were highly diverged from each other and each lineage had a unique genetic profile. The evaluation of mtDNA PCR-RFLP data coupled with geological history of Anatolia indicated a deep genetic divergence among the mtDNA haplotypes of G. rufa populations from drainages of the Mediterranean and Persian Gulf, suggesting an early isolation of Tigris-Euphrates with Orontes river and other rivers draining into the Mediterranean Sea. In general, data from both mtDNA and nDNA were congruent.     

Lineage origin and expansion of a Neotropical migrant songbird after recent glaciation events

Birds of the Northern Hemisphere often harbour the genetic signature of postglaciation expansion but analyses identifying the location of refugia and the directionality of expansions are rare. Here we explore the evolutionary history of yellow warbler lineages, focusing on how these lineages recolonized their current range. We genotyped samples from 696 yellow warblers via direct sequencing of a 333-bp control region I mitochondrial DNA fragment or lineage-specific genotyping. Phylogenetic analysis revealed two monophyletic clades: a highly migratory group including previously identified eastern and western lineages and a less migratory group including a lineage consisting of tropical residents and a new 'southern' lineage localized in southwest United States. We then modelled the expansion of the eastern and western lineages, identified the location of potential refugia and assessed the importance of migration as a historical factor promoting gene flow. The expansion of the eastern lineage proceeded from a main refugia in the eastern United States, with possible contribution of an additional local refugia. In the western lineage, the expansion proceeded from a single refugia possibly located in western United States. Because two lineages overlapped to varying degrees in central North America, we suggest that the Canadian Prairies offered a bridge of riparian habitats where the lineages met after glacier retreat, while the US Central Great Plains acted as a barrier that limited secondary contact. Finally, gene flow was more important along the north-south axis of migration than away from it, suggesting spring migration played a role in the dispersal of lineages.     

Cryptic diversity in the mtDNA of the ornamental fish Carnegiella strigata

Mitochondrial DNA ( mtDNA) sequences of the marbled hatchetfish Carnegiella strigata, an ornamental fish exported from the Negro River, was examined to determine its genetic diversity and population structure in blackwater rivers (Negro and Uatumã Rivers) in the central Amazon. Analyses of a 646 bp fragment of the ATPase 6/8 mtDNA gene revealed two monophyletic lineages of C. strigata with considerable genetic distance between them (10–12%), suggesting that these lineages should not be considered a single stock. Furthermore, there were strong differences in the geographical distribution of the lineages. These results indicate a past association between drainages of the Negro and Uatumã Rivers. They also suggest that, in the Negro River, its main tributary, the Branco River, may act as a geographical barrier and potentially an ecological barrier between populations of the middle and lower portions of the river.     

MITOCHONDRIAL DNA VARIATION IN THE FIELD VOLE (MICROTUS AGRESTIS): REGIONAL POPULATION STRUCTURE AND COLONIZATION HISTORY

Restriction fragment length polymorphism analysis of mitochondrial DNA (mtDNA) was used to examine the genetic structure among field voles (Microtus agrestis) from southern and central Sweden. A total of 57 haplotypes was identified in 158 voles from 60 localities. Overall mtDNA diversity was high, but both haplotype and nucleotide diversity exhibited pronounced geographic heterogeneity. Phylogenetic analyses revealed a shallow tree with seven primary mtDNA lineages separated by sequence divergences ranging from 0.6% to 1.0%. The geographic structure of mtDNA diversity and lineage distribution was complex but strongly structured and deviated significantly from an equilibrium situation. The extensive mtDNA diversity observed and the recent biogeographic history of the region suggests that the shallow mtDNA structure in the field vole cannot be explained solely by stochastic lineage sorting in situ or isolation by distance. Instead, the data suggest that the genetic imprints of historical demographic conditions and vicariant geographic events have been preserved and to a large extent determine the contemporary geographic distribution of mtDNA variation. A plausible historical scenario involves differentiation of mtDNA lineages in local populations in glacial refugia, a moving postglacial population structure, and bottlenecks and expansions of mtDNA lineages during the postglacial recolonization of Sweden. By combining the mtDNA data with an analysis of Y-chromosome variation, a specific population unit was identified in southwestern Sweden. This population, defined by a unique mtDNA lineage and fixation of a Y-chromosome variant, probably originated in a population bottleneck in southern Sweden about 12,000 to 13,000 calendar years ago.     

Mitochondrial diversity of Opsariichthys bidens (Teleostei, Cyprinidae) in three Chinese drainages

We describe the phylogeographic structure of 28 Chinese populations of the cyprinid Opsariichthys bidens across three main Chinese river drainages. Our study is based on the phylogenetic analysis of the complete mitochondrial cytochrome b gene (1140 bp). We combined this analysis with population processes inferred from nested clade analysis (NCA) and mismatch distributions. Both analyses showed that Chinese O. bidens consists of five mtDNA lineages (Opsariichthys 1-5) with high genetic divergence among them. Molecular divergences (TrN+G) higher than 20% among the Opsariichthys 1-5 mtDNA lineages suggest a taxonomic underestimation at the species level. About 92% of the genetic variance among samples was explained by differences among Opsariichthys mtDNA lineages. Drainage-restricted haplotypes with high frequencies and moderate nucleotide diversity show that Opsariichthys populations have evolved independently. NCA results were congruent with the phylogeny, and unimodal mismatch distributions with negative Tajima's D values suggest population expansions in some Opsariichthys lineages. The phylogeographic structure of the Opsariichthys 1-5 mtDNA lineages appears to be related to their long-term interruption of gene flow (theta(ST)>0.97). Our results suggested that fragmentation of ancestral ranges might have caused Opsariichthys diversification in Chinese waters. However, current distribution of common haplotypes across the Yangtze and Pearl drainages suggests a recent river connection that could have favoured gene flow across drainages. Overall, the results indicated that the richness of current Asian widespread species might have been underestimated, and that the cyprinid populations of O. bidens in the Yangtze, Pearl and Hai He drainages may correspond to five species.     

Changes in genetic diversity and differentiation in Red‐cockaded woodpeckers (Dryobates borealis) over the past century

Red‐cockaded woodpeckers (RCW; Dryobates borealis) declined after human activities reduced their fire‐maintained pine ecosystem to <3% of its historical range in the southeastern United States and degraded remaining habitat. An estimated 1.6 million RCW cooperative breeding groups declined to about 3,500 groups with no more than 10,000 birds by 1978. Management has increased RCW population abundances since they were at their lowest in the 1990s. However, no range‐wide study has been undertaken since then to investigate the impacts of this massive bottleneck or infer the effects of conservation management and recent demographic recoveries. We used mitochondrial DNA sequences (mtDNA) and nine nuclear microsatellite loci to determine if range‐wide demographic declines resulted in changes to genetic structure and diversity in RCW by comparing samples collected before 1970 (mtDNA data only), between 1992 and 1995 (mtDNA and microsatellites), and between 2010 and 2014 (mtDNA and microsatellites). We show that genetic diversity has been lost as detected by a reduction in the number of mitochondrial haplotypes. This reduction was apparent in comparisons of pre‐1970 mtDNA data with data from the 1992–1995 and 2010–2014 time points, with no change between the latter two time points in mtDNA and microsatellite analyses. The mtDNA data also revealed increases in range‐wide genetic differentiation, with a genetically panmictic population present throughout the southeastern United States in the pre‐1970s data and subsequent development of genetic structure that has remained unchanged since the 1990s. Genetic structure was also uncovered with the microsatellite data, which like the mtDNA data showed little change between the 1992–1995 and 2010–2014 data sets. Temporal haplotype networks revealed a consistent, star‐like phylogeny, suggesting that despite the overall loss of haplotypes, no phylogenetically distinct mtDNA lineages were lost when the population declined. Our results may suggest that management during the last two decades has prevented additional losses of genetic diversity.     

Effects of Pleistocene climatic and geomorphological changes on the population structure of the restricted-range catfish Trichogenes longipinnis (Siluriformes: Trichomycteridae)

Trichogenes longipinnis Britski & Ortega is a narrowly distributed endemic and phenotypically variable catfish from the coastal basins of the Serra do Mar range in southeast Brazil. We examined patterns of mtDNA variation of this species in coastal basins of the Serra do Mar to determine the influences of past climatic and geomorphological processes in connection with the currently isolated basins. Allozyme data were also used to test the hypothesis that the different spotting patterns in the different areas could be the result of cryptic speciation. Regardless of body pigmentation, T. longipinnis specimens from across the basins were found to belong to a single species, but the populations were structured in accordance with the current hydrological watersheds, in four management units across the three distinct basins of its geographic distribution. Thus, the current genetic distribution may be best explained by both marine regressions and orogeny. Based on the low levels of genetic variation and high population structure observed, we suggest that T. longipinnis should be classified as “vulnerable” in the Brazilian red list of threatened fauna. Furthermore, we propose that the headwaters of the Parati-Mirim River basin should be incorporated as an extension of the Bocaina National Park to protect its genetically differentiated lineages.     

Genetic structure analysis of three Hispanic populations from Costa Rica, Mexico, and the southwestern United States using Y-chromosome STR markers and mtDNA sequences

Two hundred seventeen male subjects from Costa Rica, Mexico, and the Hispanic population of the southwestern United States were studied. Twelve Y-chromosome STRs and the HVSI sequence of the mtDNA were analyzed to describe their genetic structure and to compare maternal and paternal lineages. All subjects are part of two NIMH-funded studies to localize schizophrenia susceptibility genes in Hispanic populations of Mexican and Central American ancestry. We showed that these three populations are similar in their internal genetic characteristics, as revealed by analyses of mtDNA and Y-chromosome STR diversity. These populations are related through their maternal lineage in a stronger way than through their paternal lineage, because a higher number of shared haplotypes and polymorphisms are seen in the mtDNA (compared to Y-chromosome STRs). These results provide evidence of previous contact between the three populations and shared histories. An analysis of molecular variance revealed no genetic differentiation for the mtDNA for the three populations, but differentiation was detected in the Y-chromosome STRs. Genetic distance analysis showed that the three populations are closely related, probably as a result of migration between close neighbors, as indicated by shared haplotypes and their demographic histories. This relationship could be an important common feature for genetic studies in Latin American and Hispanic populations.