Fine-scale Genetic Analyses Research Articles

Assessing Niche Dynamics and Population Connectivity in an Endangered Tree Species, Emmenopterys henryi: Implications for Conservation and Management

Understanding the niche dynamic among distinct populations and delineating the dispersal corridors that exist between them under current climates is critical for elucidating the contemporary forces driving genetic divergence, facilitating population connectivity, and informing targeted conservation efforts, particularly for species exhibiting pronounced intraspecific lineages. In this study, we focus on evaluating the range and niche dynamics of the intraspecific lineages of Emmenopterys henryi and exploring potential patterns of population connectivity both within and across these lineages. Our findings unveiled a significant niche divergence between the two intraspecific lineages, characterized by limited overlap in climatic conditions and suitable ranges. Furthermore, our analysis of population connectivity revealed the presence of dispersal routes with varying degrees of connectivity within each lineage, while low connectivity was observed between the two lineages. Our results highlight the critical role of fine-scale ecological niche models (ENMs) and genetic connectivity analyses in elucidating the complexities of niche evolution and genetic connectivity, particularly for species with discrete intraspecific lineages. In addition, given the fact that rapid genetic erosion of species inhabiting the regions we focus on in this study is often associated with habitat loss and fragmentation, our findings will also offer valuable insights for designing targeted conservation strategies aimed at restoring connectivity and increasing local population sizes for this endangered species.

Extensive genetic admixture between Tai-Kadai-speaking people and their neighbours in the northeastern region of the Yungui Plateau inferred from genome-wide variations

BackgroundYungui Plateau in Southwest China is characterized by multi-language and multi-ethnic communities and is one of the regions with the wealthiest ethnolinguistic, cultural and genetic diversity in East Asia. There are numerous Tai-Kadai (TK)-speaking populations, but their detailed evolutionary history and biological adaptations are still unclear.ResultsHere, we genotyped genome-wide SNP data of 77 unrelated TK-speaking Zhuang and Dong individuals from the Yungui Plateau and explored their detailed admixture history and adaptive features using clustering patterns, allele frequency differentiation and sharing haplotype patterns. TK-speaking Zhuang and Dong people in Guizhou are closely related to geographically close TK and Hmong-Mien (HM)-speaking populations. Besides, we identified that Guizhou TK-speaking people have a close genetic relationship with Austronesian (AN)-speaking Atayal and Paiwan people, which is supported by the common origin of the ancient Baiyue tribe. We additionally found subtle genetic differences among the newly studied TK people and previously reported Dais via the fine-scale genetic substructure analysis based on the shared haplotype chunks. Finally, we identified specific selection candidate signatures associated with several essential human immune systems and neurological disorders, which could provide evolutionary evidence for the allele frequency distribution pattern of genetic risk loci.ConclusionsOur comprehensive genetic characterization of TK people suggested the strong genetic affinity within TK groups and extensive gene flow with geographically close HM and Han people. We also provided genetic evidence that supported the common origin hypothesis of TK and AN people. The best-fitted admixture models further suggested that ancestral sources from northern millet farmers and southern inland and coastal people contributed to the formation of the gene pool of the Zhuang and Dong people.

Comparative reproductive ecology of two sister Asarum species (Aristolochiaceae) in relation to the evolution of elongated floral appendage.

Genus Asarum (Aristolochiaceae) shows diverse floral morphology and is hypothesized to have diversified as a result of pollinator-mediated selection. Yet most aspects of their reproductive ecology, including pollinators, remain unclear. This study focuses on A. costatum and A. minamitanianum in Japan, a sister species pair having remarkable differences in calyx lobe length (10-20 mm and 70-180 mm, respectively). The objectives of this study are to elucidate multiple aspects of reproductive ecology of these two species and obtain evolutionary insights into floral organ elongation. We adopted combined approaches, including field observations, molecular analyses and cultivation experiments, such as pollinator observation for 3 years, fine-scale spatial genetic analysis of 769 individuals, paternity analysis based on 566 seeds over 4 years, and control pollination experiments. Both Asarum species had strong spatial genetic structures, indicating limited seed dispersal. Pollinator observation revealed that flies and ground-dwelling insects visited flowers of both species, but that the pollinator fauna differed between the species. The visitation rate of flies was extremely low but was more than twice as high in the species with an elongated floral appendage. Paternity analysis revealed A. minamitanianum was predominantly outcrossing, while A. costatum showed a wide range of selfing rates among fruits. These two Asarum species are likely adapted to fly pollination in the shady forest understorey, where available pollinator fauna is limited. In addition, although its function remains unclear, the elongated calyx lobe of A. minamitanianum could have evolved for effective pollen dispersal by attracting fly visitors.

Population Genetics of Sugar Kelp Throughout the Northeastern United States Using Genome-Wide Markers

An assessment of genetic diversity of marine populations is critical not only for the understanding and preservation of natural biodiversity but also for its economic potential. As commercial demand rises for marine resources, it is critical to generate baseline information for monitoring wild populations. Furthermore, anthropogenic stressors on the coastal environment, such as warming sea surface temperatures and overharvesting of wild populations, are leading to the destruction of keystone marine species such as kelps. In this study, we conducted a fine-scale genetic analysis using genome-wide high-density markers on Northwest Atlantic sugar kelp species, Saccharina latissima and putative species, Saccharina angustissima . The population structure for a total of 149 samples from the Gulf of Maine (GOM) and Southern New England (SNE) was investigated using AMOVA, Fst, admixture, and PCoA. Genome-wide association analyses were conducted for six morphological traits, and the extended Lewontin and Krakauer (FLK) test was used to detect selection signatures. Our results indicate that the GOM region is moderately more heterogeneous than SNE. While admixture was observed between regions, these results confirm that Cape Cod acts as a biogeographic barrier for sugar kelp gene flow. We detected one significant SNP (P-value=2.03×10 -7 ) associated with stipe length, and 243 SNPs with higher-than-neutral differentiation. The findings of this study provide fundamental knowledge on sugar kelp population genetics for future monitoring, managing and potentially restoring wild populations, as well as assisting in selective breeding to improve desirable traits for cultivation and bioenergy production.

Genetic Structure of Calophylluminophyllum L. in Dompu Natural Forest

Calophylluminophyllum is an indigenous species and distributed mostly at shoreline areas in Indonesia. Genetic conservation of this species inits natural habitats is very important. A study aimed to assess genetic diversity and structure of C. inophyllum at Dompu natural forestwas carried out. Leaf samples were collected from three natural populations at Dompuregency (Kilo, Kempo and Pekat). Genetic analysis was carried out using six simple sequence repeats (SSR) markers. Private alleles were only found at Kilo population. Number of detected alleles (NA), values of alleles diversity (AR) and gene diversity (HE) were also higher at Kilo (NA: 17; AR: 2.219; HE: 0.339) than at Kempo (NA: 10; AR: 1.661; HE: 0.219) and Pekat (NA: 12; AR: 1.941; HE: 0.276). The values of the inbreeding coefficients (FIS) were insignificant among the populations. The medium- scale genetic structure showed that genetic relations. Fine-scale genetic structure analysis showed insignificant genetic structure among trees in distance of 2 m at Kilo and 400 m at Pekat, respectively, suggesting that C. inophyllum was dispersed as far as 2 m to 400 m.

Assessing Cryptic Invasion State: Fine-Scale Genetic Analysis of Ciona savignyi Population in Putative Native Habitat of the Korean Coast

The solitary ascidian, Ciona savignyi (Ascidiacea, Enterogona) is a notorious marine invader still expanding its habitat range worldwide. This species is considered native to the North West Pacific, but its indigeneity in Korean coastal waters has been questioned because of outdated taxonomic records and its inhabitation of oceanographically marginal areas. To clarify their cryptic invasion state, 247 individual C. savignyi samples were collected from 12 harbors and marinas on the Korean coast, and a 744 bp region of mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I gene was sequenced and analyzed. Our analyses of population genetic structure and demographic history provided considerable pieces of evidence supporting their long-term establishment on the Korean coasts: differentiated population genetic structure, sequentially arrayed star-shape haplotype network, neutrality test results of past population expansions, and post-glacial colonization pattern of demography. Consequently, we concluded that C. savignyi populations on the Korean Coast are indigenous rather than exotic. These results could be used as reference data for further phylogeo graphic and demographic studies of problematic Ciona species, and to clarify and resolve similar cryptic invasion states of the other Korean coastal marine organisms. This study is the first to resolve the cryptic in vasion state of Korean marine organisms using genetic analysis.

Isolation and characterization of eleven novel microsatellite markers for fine-scale population genetic analyses of Gammarus pulex (Crustacea: Amphipoda).

The freshwater amphipod species Gammarus pulex (Linnaeus, 1758) is widespread across Europe and Asia and is able to live in a broad range of environmental conditions. Yet, it is of great interest to which degree it is able to tolerate and adapt to the current rapid anthropogenic environmental changes affecting its habitat, such as pollution, changes in river morphology, and invasions of alien gammarid species. Microsatellite primers for genetic population studies with G. pulex have been developed but due to the existence of several genetically different lineages within the species, the application of these primers is not always successful. In order to investigate the impacts of anthropogenic environmental changes on the spatio-genetic patterns of G. pulex lineage E in streams in the Saale river catchment in Germany, we designed eleven novel polymorphic microsatellites for this lineage using a high-throughput sequencing approach. These microsatellites enabled highly specific characterization of three closely related populations. The results show genetically distinct populations reflected by both a principal coordinates analysis and an analysis of molecular variance. Several of the newly designed microsatellite primers also enabled successful cross-amplification of the respective microsatellites in specimens of G. pulex lineage C, while only two microsatellites were amplified successfully and showed polymorphisms for all of the analyzed specimens of G. fossarum Koch, 1836. The microsatellites identified here are suitable for future assessments of micro-evolutionary dynamics of G. pulex from central Germany.

Fine-scale hierarchical genetic structure and kinship analysis of the ascidian Pyura chilensis in the southeastern Pacific.

Studying population structure and genetic diversity at fine spatial scales is key for a better understanding of demographic processes that influence population connectivity. This is particularly important in marine benthic organisms that rely on larval dispersal to maintain connectivity among populations. Here, we report the results of a genetic survey of the ascidian Pyura chilensis from three localities along the southeastern Pacific. This study follows up on a previous report that described a genetic break in this region among localities only 20 km apart. By implementing a hierarchical sampling design at four spatial levels and using ten polymorphic microsatellite markers, we test whether differences in fine‐scale population structure explain the previously reported genetic break. We compared genetic spatial autocorrelations, as well as kinship and relatedness distributions within and among localities adjacent to the genetic break. We found no evidence of significant autocorrelation at the scale up to 50 m despite the low dispersal potential of P. chilensis that has been reported in the literature. We also found that the proportion of related individuals in close proximity (<1 km) was higher than the proportion of related individuals further apart. These results were consistent in the three localities. Our results suggest that the spatial distribution of related individuals can be nonrandom at small spatial scales and suggests that dispersal might be occasionally limited in this species or that larval cohorts can disperse in the plankton as clustered groups. Overall, this study sheds light on new aspects of the life of this ascidian as well as confirms the presence of a genetic break at 39°S latitude. Also, our data indicate there is not enough evidence to confirm that this genetic break can be explained by differences in fine‐scale genetic patterns among localities.

Identification of a contact zone and hybridization for two subspecies of the American pika (Ochotona princeps) within a single protected area

Genetic variation is the basis upon which natural selection acts to yield evolutionary change. In a rapidly changing environment, increasing genetic variation should increase evolutionary potential, particularly for small, isolated populations. However, the introduction of new alleles, either through natural or human-mediated processes, may have unpredictable consequences such as outbreeding depression. In this study, we identified a contact zone and limited gene flow between historically separated genetic lineages of American pikas (Ochotona princeps), representing the northern and southern Rocky Mountain subspecies, within Rocky Mountain National Park. The limited spatial extent of gene flow observed may be the result of geographic barriers to dispersal, selection against hybrid individuals, or both. Our fine-scale population genetic analysis suggests gene flow is limited but not completely obstructed by extreme topography such as glacial valleys, as well as streams including the Colorado River. The discovery of two subspecies within this single protected area has implications for monitoring and management, particularly in the light of recent analyses suggesting that the pikas in this park are vulnerable to fragmentation and local extinction under future projected climates. Future research should focus on the fitness consequences of introgression among distinct genetic lineages in this location and elsewhere, as well as within the context of genetic rescue as a conservation and management strategy for a climate sensitive species.

Construction of a normalized full-length cDNA library of cephalopod Amphioctopus fangsiao and development of microsatellite markers

Amphioctopus fangsiao is one of the most economically important species and has been considered to be a candidate for aquaculture. In order to facilitate its fine-scale genetic analyses, we constructed a normalized full-length library successfully and developed a set of microsatellite markers in this study. The normalized full-length library had a storage capacity of 6.9×105 independent clones. The recombination efficiency was 95% and the average size of inserted fragments was longer than 1000 bp. A total of 3440 high quality ESTs were obtained, which were assembled into 1803 unigenes. Of these unigenes, 450 (25%) were assigned into 33 Gene Ontology terms, 576 (31.9%) into 153 Kyoto Encyclopedia of Genes and Genomes pathways, and 275 (15.3%) into 22 Clusters of Orthologous Groups. Seventy-six polymorphic microsatellite markers were identified. The number of alleles per locus ranged from 4 to 17, and the observed and expected heterozygosities varied between 0.167 and 0.967 and between 0.326 and 0.944, respectively. Twelve loci were significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction and no linkage disequilibrium was found between different loci. This study provided not only a useful resource for the isolation of the functional genes, but also a set of informative microsatellites for the assessment of population structure and conservation genetics of A. fangsiao.

Novel microsatellite markers for Pyura chilensis reveal fine-scale genetic structure along the southern coast of Chile

Studying the geographic scale of gene flow and population structure in marine populations can be a powerful tool with which to infer patterns of larval dispersal averaged across generations. Here, we describe the development of ten novel polymorphic microsatellite markers for an important endemic ascidian, Pyura chilensis, of the southeastern Pacific, and we report the results from fine-scale genetic structure analysis of 151 P. chilensis individuals sampled from five sites constituting ∼80 km of coastline in southern Chile. All microsatellite markers were highly polymorphic (number of alleles ranged from 12 to 36). Our results revealed significant deviations from Hardy–Weinberg equilibrium (HWE) for most loci, suggesting the presence of either null alleles or deviations from random mating within sampled sites. However, we found a significantly higher spatial autocorrelation and higher mean pairwise relatedness among individuals sampled from the same sites than would be expected if samples were randomly distributed across all sites; this suggests that spatial configuration and reproduction might not be random within sites. Our results indicate the presence of a weak but significant genetic structure between sites (overall F ST = 0.015, p < 0.001). Despite the short pelagic larval duration of this species, geographic distance does not appear to correlate with genetic distances between sites. From the results gathered here, it seems possible that genetic structure at this spatial scale is driven to some extent by local population dynamics (deviations from random mating and/or a large proportion of larvae settling in proximity of relatives), yet infrequent long-distance dispersal events might also be responsible for the relatively weak spatial heterogeneity between sites. Overall, our results both highlight the utility of this new marker set for population genetic studies of this species and provide new evidence regarding the complexity of the small-scale population structure of this species.

Development and characterization of microsatellite markers for Solen grandis using Illumina sequencing approach.

Solen grandis is an important economic and overexploited bivalve species. In order to perform its fine-scale genetic analyses, 105 pairs of microsatellites with polymorphism were identified through Illumina Hiseq platform and bioinformatic assembly technology in this study. The estimated fragment size ranged from 100 to 268 bp and the number of alleles per locus varied between 2 and 23. Observed and expected heterozygosities varied from 0.0667 to 1.0000 and 0.0966 to 0.9492, respectively. Fourteen loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni correction. These microsatellite markers developed in this study would be helpful for future genetic studies on S. grandis and closely related species.

Development and characterization of 29 microsatellite markers for Ligumia nasuta (Bivalvia: Unionidae) using an Illumina sequencing approach

Ligumia nasuta (Say, 1817; Eastern Pondmussel) is an imperiled freshwater mussel (Unionidae) in eastern North America. Population declines in the Laurentian Great Lakes resulting from the introduction of dreissenid mussels and habitat destruction in the 20th Century have greatly reduced and limited its distribution. To properly inform restoration and management efforts for L. nasuta, fine-scale genetic analyses must be performed on the remnant populations. This study used Illumina paired-end shotgun sequencing to identify potential microsatellite loci for L. nasuta, utilizing two samples to develop the Illumina paired-end shotgun library. Forty-eight primer pairs were tested on the remaining 24 samples. Twenty-nine of the 48 microsatellite primer sets screened were successfully amplified using 24 L. nasuta samples collected from the Great Lakes watershed. The estimated fragment size ranged from 167 to 445 base-pairs (bp) and the number of alleles per locus varied between 5 and 16 (mean = 9.7). Only five of the loci deviated significantly from Hardy–Weinberg expectations after Bonferroni corrections. The development of these new microsatellite loci will greatly facilitate future genetic studies on L. nasuta.

Evaluation of fire recurrence effect on genetic diversity in maritime pine (Pinus pinaster Ait.) stands using Inter-Simple Sequence Repeat profiles

The management of maritime pine in fire-prone habitats is a challenging task and fine-scale population genetic analyses are necessary to check if different fire recurrences affect genetic variability. The objective of this study was to assess the effect of fire recurrence on maritime pine genetic diversity using inter-simple sequence repeat markers (ISSR). Three maritime pine (Pinus pinaster Ait.) populations from Northern Portugal were chosen to characterize the genetic variability among populations. In relation to fire recurrence, Seirós population was affected by fire both in 1990 and 2005 whereas Vila Seca-2 population was affected by fire just in 2005. The Vila Seca-1 population has been never affected by fire. Our results showed the highest Nei's genetic diversity (He=0.320), Shannon information index (I=0.474) and polymorphic loci (PPL=87.79%) among samples from twice burned populations (Seirós site). Thus, fire regime plays an important role affecting genetic diversity in the short-term, although not generating maritime pine genetic erosion.

Development and characterization of polymorphic microsatellite markers in neotropical fish of the genusApistogramma(Perciformes: Labroidei: Cichlidae)

The South American genus of Cichlid fish Apistogramma comprises over 100 species, most of which are difficult to identify. There is a need to clarify species limits and evolutionary relationships, conduct fine-scale phylogeographic revision of some species complexes, and collect information on population conservation status. In addition, recent studies suggest that female mate choice may lead to reproductive isolation and potentially to sympatric speciation in some species. Highly variable bi-parentally inherited molecular markers are needed to determine reproductive units in order to test this hypothesis. Microsatellite markers were developed for fine-scale population genetic analyses within the genus Apistogramma, based on a DNA library of 7567 candidate loci. A set of 40 loci with dinucleotide repeats was selected and tested for amplification and dimorphism in three Apistogramma species (six samples). Thirteen polymorphic loci, combined in three multiplex sets, were retained and analyzed in nine Apistogramma species (47 samples) representative of the genus diversity in the Peruvian Amazon basin. All loci presented a high level of heterozygosity and polymorphism in most species. This will be helpful in evolutionary genetics and conservation studies.

Genetic and morphological evidence for introgression between three species of willows.

BackgroundHybridization and introgression are said to occur relatively frequently in plants, and in particular among different species of willows. However, data on the actual frequency of natural hybridization and introgression is rare. Here, we report the first fine-scale genetic analysis of a contact zone shared between the three basket willow species, Salix dasyclados, S. schwerinii and S. viminalis in the vicinity of the Lake Baikal in Southern Siberia. Individuals were sampled in fourteen populations and classified as pure species or hybrids based on a set of morphological characters. They were then genotyped at 384 nuclear SNP and four chloroplast SSR loci. The STRUCTURE and NewHybrids softwares were used to estimate the frequency and direction of hybridization using genotypic data at the nuclear SNP loci.ResultsAs many as 19 % of the genotyped individuals were classified as introgressed individuals and these were mainly encountered in the centre of the contact zone. All introgressed individuals were backcrosses to S. viminalis or S. schwerinii and no F1 or F2 hybrids were found. The rest of the genotyped individuals were classified as pure species and formed two clusters, one with S. schwerinii individuals and the other with S. viminalis and S. dasyclados individuals. The two clusters were significantly genetically differentiated, with FST = 0.333 (0.282–0.382, p < 0.001). In contrast, for the chloroplast haplotypes, no genetic differentiation was observed as they were completely shared between the species. Based on morphological classification only 5 % of the individuals were classified as introgressed individuals, which was much less than what was detected using genotypic data.ConclusionsWe have discovered a new willow hybrid zone with relatively high frequency of introgressed individuals. The low frequency of F1 hybrids indicates that ongoing hybridization is limited, which could be because of the presence of reproductive barriers or simply because the conditions are not favorable for hybridization. We further conclude that in order to get a complete picture of the species composition of a hybrid zone it is necessary to use a combination of morphological characters and genetic data from both nuclear and chloroplast markers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0461-7) contains supplementary material, which is available to authorized users.

New possibilities arise for studies of hybridization: SNP-based markers for the multi-species Daphnia longispina complex derived from transcriptome data

In order to trace community dynamics and reticulate evolution in hybrid species complexes, long-term comparative studies of natural populations are necessary. Such studies require the development of tools for fine-scale genetic analyses. In the present study, we developed species-diagnostic SNP-based markers for hybridizing freshwater crustaceans: the multispecies Daphnia longispina complex. Specifically, we took advantage of transcriptome data from a key species of this hybrid complex, the annotated genome of a related Daphnia species and well-defined reference genotypes from three parental species. Altogether eleven nuclear loci with several species-specific SNP sites were identified in sequence alignments of these reference genotypes from three parental species and their interspecific hybrids. A PCR-RFLP assay was developed for cost-efficient large population screening by SNP-based genotyping. Taxon assignment by RFLP patterns was nearly perfectly concordant with microsatellite genotyping across several screened populations from Europe. Finally, we were able to amplify two short regions of these loci in formaldehyde-preserved samples dating back to the year 1960. The species-specific SNP-based markers developed here provide valuable tools to study hybridization over time, including the long-term impact of various environmental factors on hybridization and biodiversity changes. SNP-based genotyping will finally allow eco-evolutionary dynamics to be revealed at different time scales.

Fine-scale genetic analysis of the exploited Nile monitor (Varanus niloticus) in Sahelian Africa.

BackgroundOverexploitation of wildlife populations results in direct consequences, such as extinction and local extirpation, as well as indirect effects including genetic diversity loss and changes in genetic structure. A clear understanding of the underlying genetic patterns of harvested species is necessary for sustainable management. The Nile monitor (Varanus niloticus) is a commercially valuable species in the international leather industry, with the highest levels of exploitation concentrated throughout Sahelian Africa. In this study, we examined the fine-scale genetic patterns of V. niloticus populations in the Sahel, with the expectation that the genetic structure would correspond to riverine drainage basins. The analyses were based on genotypes at 11 microsatellite loci for 318 individuals, spanning three separate watersheds throughout the Sahel.ResultsOur analyses identified four genetic clusters throughout the region, one of which (the westernmost population) exhibited very high levels of genetic differentiation (FST = 0.47). Contrary to our expectation, the largest genetic break occurred within a single watershed, the Niger basin, rather than between watersheds. However, other localities displayed evidence of reduced gene flow between watershed boundaries. Across methods, the westernmost population exhibited lower estimates of Ne as well as lower levels of genetic diversity compared to the other inferred populations. While we did not detect evidence for recent population bottlenecks, our analyses indicated historic population declines around 1,000–1,800 years ago.ConclusionWe found that the underlying genetic structure of Varanus niloticus across Sahelian Africa reflects historic as well as present-day patterns of riverine drainages. The high degree of differentiation found for the westernmost population indicates the presence of a separate lineage, and should be taken into consideration when setting harvest limits. The historic population decline for two of the populations corresponds to a drastic expansion of an ancient human civilization in the region, suggesting that human exploitation of V. niloticus has a longer history than previously thought.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0188-x) contains supplementary material, which is available to authorized users.

Population ecology and genetics of the invasive lionfish in Puerto Rico

The lionfish (Pterois volitans), has become an abundant alien species along the southeast coast of the United States of America and in Caribbean coastal waters. Although, they represent a major concern in conservation, no studies have yet assessed their population ecology and genetic structure simultaneously. We collected 227 lionfish from 24 sites around Puerto Rico to investigate, the length distribution, length-weight relationships, relative condition factor, and mitochondrial DNA (mtDNA) genetic diversity. The total length distribution ranged between 37 and 349 mm with a single peak between 130 and 149 mm. Our analysis indicated isometric growth for mature individuals and a positive allometric growth for immature lionfishes. These results suggest a different allocation of resources, most likely reproduction for mature individuals and somatic growth for the immature lionfish. The relative condition factor (KN) was similar for immature and mature individuals. Genetic analyses indicated that P. volitans is the only lionfish species present in Puerto Rico, and that its origin was likely dispersal from the epicenter of introduction off the coast of Florida. Interestingly, only four of the nine mtDNA haplotypes identified in the Atlantic were observed in the Puerto Rican population. A fine-scale population genetic analysis suggested a significantly different population structure between the west and south coasts. Finally, our data suggests a second founder effect, but with a reduction of haplotype diversity.

Relatedness and other finescale population genetic analyses in the threatened eastern box turtle (Terrapene c. carolina) suggest unexpectedly high vagility with important conservation implications

Genetic analyses of populations are essential to the conservation of threatened and cryptic taxa such as Chelonians. Turtles and tortoises are among the most imperiled vertebrate taxa worldwide, yet many of the natural history traits remain unknown leaving management decisions ill- or improperly informed. The eastern box turtle Terrapene c. carolina is no exception, with many gaps in our knowledge about traits such as juvenile dispersal and patterns of relatedness across the landscape, especially as it is a species not particularly tied to water and vulnerable to human disturbance. In addition, all long-term studies of this species have documented demographic population declines, even in protected habitats. In this study we explore finescale population structuring, gene flow, dispersal, and relatedness at four sites across the species range. These sites vary in habitat fragmentation and surrounding habitat quality. Many radiotelemtery and mark-recapture studies suggest that Terrapene spp. have a sedentary natural history, with small and temporally conserved home ranges and little propensity for dispersal. Based on these data we predicted that populations would be highly structured at fine geographic scales, closely related individuals (1st- and 2nd-degree relatives) would coexist in close proximity, and individuals exhibiting transient behavior would be true transients. All sites had low levels of population structuring, mean pairwise relatedness values were statistically zero, over 90 % of pairs of individuals were unrelated, 4.4–8.7 % were half-siblings, and fewer than 1.0 % were full siblings or parent-offspring pairs. These patterns were consistent across all four sites, regardless of habitat fragmentation. Furthermore, while some related pairs were found within a few meters of each other, others ranged up to 33 km apart. We found that one of two individuals with transient behavior was indeed a true genetic transient. These findings suggest that box turtles may be much more vagile than current management practices recognize. As most turtle species are strongly affected by anthropogenic disturbance, many may require much larger contiguous blocks of intact habitat for species persistence as the box turtle likely does. Management plans may therefore need to be updated to allow for safe and effective long-distance dispersal at the appropriate spatial scales in order to maintain genetic health of these species.