Population genetic structure and gene flow of Adélie penguins (Pygoscelis adeliae) breeding throughout the western Antarctic Peninsula

2017 ◽  
Vol 29 (6) ◽  
pp. 499-510 ◽  
Author(s):  
Kristen B. Gorman ◽  
Sandra L. Talbot ◽  
Sarah A. Sonsthagen ◽  
George K. Sage ◽  
Meg C. Gravely ◽  
...  

AbstractAdélie penguins (Pygoscelis adeliae) are responding to ocean–climate variability throughout the marine ecosystem of the western Antarctic Peninsula (WAP) where some breeding colonies have declined by 80%. Nuclear and mitochondrial DNA (mtDNA) markers were used to understand historical population genetic structure and gene flow given relatively recent and continuing reductions in sea ice habitats and changes in numbers of breeding adults at colonies throughout the WAP. Genetic diversity, spatial genetic structure, genetic signatures of fluctuations in population demography and gene flow were assessed in four regional Adélie penguin colonies. The analyses indicated little genetic structure overall based on bi-parentally inherited microsatellite markers (FST=-0.006–0.004). No significant variance was observed in overall haplotype frequency (mtDNAΦST=0.017;P=0.112). Some comparisons with Charcot Island were significant, suggestive of female-biased philopatry. Estimates of gene flow based on a two-population coalescent model were asymmetrical from the species’ regional core to its northern range. Breeding Adélie penguins of the WAP are a panmictic population and hold adequate genetic diversity and dispersal capacity to be resilient to environmental change.

Heredity ◽  
2020 ◽  
Vol 126 (1) ◽  
pp. 63-76
Author(s):  
Sarah M. Griffiths ◽  
Mark J. Butler ◽  
Donald C. Behringer ◽  
Thierry Pérez ◽  
Richard F. Preziosi

AbstractUnderstanding population genetic structure can help us to infer dispersal patterns, predict population resilience and design effective management strategies. For sessile species with limited dispersal, this is especially pertinent because genetic diversity and connectivity are key aspects of their resilience to environmental stressors. Here, we describe the population structure of Ircinia campana, a common Caribbean sponge subject to mass mortalities and disease. Microsatellites were used to genotype 440 individuals from 19 sites throughout the Greater Caribbean. We found strong genetic structure across the region, and significant isolation by distance across the Lesser Antilles, highlighting the influence of limited larval dispersal. We also observed spatial genetic structure patterns congruent with oceanography. This includes evidence of connectivity between sponges in the Florida Keys and the southeast coast of the United States (>700 km away) where the oceanographic environment is dominated by the strong Florida Current. Conversely, the population in southern Belize was strongly differentiated from all other sites, consistent with the presence of dispersal-limiting oceanographic features, including the Gulf of Honduras gyre. At smaller spatial scales (<100 km), sites showed heterogeneous patterns of low-level but significant genetic differentiation (chaotic genetic patchiness), indicative of temporal variability in recruitment or local selective pressures. Genetic diversity was similar across sites, but there was evidence of a genetic bottleneck at one site in Florida where past mass mortalities have occurred. These findings underscore the relationship between regional oceanography and weak larval dispersal in explaining population genetic patterns, and could inform conservation management of the species.


2015 ◽  
Vol 106 (1) ◽  
pp. 114-123 ◽  
Author(s):  
X.-T. Tang ◽  
Y. Ji ◽  
Y.-W. Chang ◽  
Y. Shen ◽  
Z.-H. Tian ◽  
...  

AbstractWhile Liriomyza sativae (Diptera: Agromyzidae), an important invasive pest of ornamentals and vegetables has been found in China for the past two decades, few studies have focused on its genetics or route of invasive. In this study, we collected 288 L. sativae individuals across 12 provinces to explore its population genetic structure and migration patterns in China using seven microsatellites. We found relatively low levels of genetic diversity but moderate population genetic structure (0.05 < FST < 0.15) in L. sativae from China. All populations deviated significantly from the Hardy–Weinberg equilibrium due to heterozygote deficiency. Molecular variance analysis revealed that more than 89% of variation was among samples within populations. A UPGMA dendrogram revealed that SH and GXNN populations formed one cluster separate from the other populations, which is in accordance with STRUCTURE and GENELAND analyses. A Mantel test indicated that genetic distance was not correlated to geographic distance (r = −0.0814, P = 0.7610), coupled with high levels of gene flow (M = 40.1–817.7), suggesting a possible anthropogenic influence on the spread of L. sativae in China and on the effect of hosts. The trend of asymmetrical gene flow was from southern to northern populations in general and did not exhibit a Bridgehead effect during the course of invasion, as can be seen by the low genetic diversity of southern populations.


2020 ◽  
Author(s):  
Cheng Jin ◽  
Huixia Kao ◽  
Shubin Dong

Abstract BackgroundStudying population genetic structure and gene flow of plant populations and their influence factors is crucial in field of conservation biology, especially rare and endangered plants. Tetraena mongolica Maxim (TM), belong to Zygophyllaceae family, a rare and endangered plant with narrow distribution. Due to excessive logging, urban expansion, industrial development and development of the scenic spot in the last decades, has caused habitat fragments and decline.ResultsIn this study, the genetic diversity, the population genetic structure and gene flow of TM populations were evaluated by reduced representation sequencing technology, a total of more than 133.45 GB high-quality clean reads and 38,097 high-quality SNPs were generated. Analysis based on multiple methods, we found existing TM populations have moderate levels of genetic diversity, very low genetic differentiation and high levels of gene flow between populations. Population structure and principal coordinates analysis showed that 8 TM populations can be divided into two groups, Mantel test detected no significant correlation between geographical distances and genetic distance for the whole sampling. The migration model indicated that the gene flow is more of an north to south migration pattern in history.ConclusionsOur study demonstrate that the present genetic structure is mainly due to habitat fragmentation caused by urban sprawl, industrial development and coal mining. For recommendations of conservation management, all 8 populations should be protected as a whole population, rather than just those in the core area of TM nature reserve, especially the populations near the edge of TM distribution in cities and industrial areas deserve our special protection.


2021 ◽  
Author(s):  
◽  
Angel Jimenez Brito

<p>Mugil cephalus is a cosmopolitan fish species found in most coastal waters from tropical to temperate zones. It is a species common in the near-shore marine environment, and known to reside in estuarine and freshwater systems. Adult M. cephalus move out to sea to spawn in aggregations. Their larvae can drift on surface ocean currents for over a month before recruitment to nursery grounds. Mugil cephalus is a species that is closely associated with the coastal environment, but it is capable of interoceanic migrations. Population genetic studies have reported high levels of genetic differentiation among populations in the Mediterranean, Atlantic and western Pacific. However, there is no evidence to suggest reproductive incompatibility has arisen among populations. In New Zealand M. cephalus supports important recreational, commercial and customary fisheries, but very little is known about the distribution and connectivity among populations.  The aim of this study was to use nuclear microsatellite DNA (msatDNA) and mitochondrial DNA (mtDNA) markers to describe the population genetic structure, connectivity patterns and to determine the phylogeographic history of New Zealand M. cephalus populations. Total of 850 samples were collected (576 adults and 274 juveniles) during the summers of 2010 and 2014-2015 from 15 locations around coastal and inland waters of the North Island, and one location in Marlborough Sounds. In addition, 245 mtDNA sequences were added from previously published studies and used to outgroup the New Zealand population and place it into the context of the other Pacific populations.  Seven msatDNA loci were isolated and used to determine the population genetic structure and connectivity patterns of M. cephalus in New Zealand. Admixture of four genetically distinct groups or populations was identified and a chaotic spatial distribution of allele frequencies. Within each population there was significant gene flow among locations, no pattern of genetic isolation-by-distance was identified and there was a high proportion of non-migrant individuals. There was evidence of bottlenecks and seasonal reproductive variation of adults, which could explain the significant shifts in the effective population size among locations.  To test whether the pattern of genetic variation in M. cephalus populations was the result of seasonal variability in the reproductive success of adults, DNA from adult and juvenile samples were used to test for differences in the levels of genetic variation between generations (cohorts). Juveniles were grouped by age classes and compared to the adults. The levels of genetic diversity within the groups of juveniles were compared to the adult population and significant genetic bottlenecks between juveniles and adults were detected. This pattern was consistent with the Sweepstake-Reproductive-Success hypothesis. Two spawning groups in the adults were identified, an early spawning group and a late spawning group.  The analysis of DNA sequence data from the mtDNA Cytochrome Oxidase subunit 1 (COX1) gene and D-loop region showed two sympatric haplogroups of M. cephalus. New Zealand was most likely colonised by M. cephalus migrants from different population sources from the Pacific first ~50,000 and a second wave of migrants from Australia between ~20, 000 and ~16,000 years ago. High levels of gene flow were detected, but there has not been enough time for genetic drift to completely sort the lineages.  The findings of this thesis research will help with the understanding of aspects of M. cephalus dispersal and the genetic structure of populations. The patterns of connectivity can be used to better align the natural boundaries of wild populations to the fishery management stock structure. Understanding the reproductive units, levels of genetic diversity and the patterns of reproduction of M. cephalus will assist management efforts to focus on the key habitats threats, risks and the long-term sustainability of the species.</p>


2004 ◽  
Vol 82 (3) ◽  
pp. 316-321 ◽  
Author(s):  
Steven R Griffin ◽  
Spencer CH Barrett

Trillium erectum L. is an insect-pollinated understory herb widespread in forests of eastern North America. Marker gene studies indicate that the species has a mixed mating system, but aspects of population genetic structure have not been investigated. Using 10 allozyme loci, we measured genetic variation within and among 23 populations sampled from throughout the species' range. Overall, T. erectum displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of loci that were polymorphic was 52%, with average values (±SE) of 1.20 ± 0.02, 0.08 ± 0.01, and 0.13 ± 0.01 for the number of alleles per locus (A), observed heterozygosity (Ho), and expected heterozygosity (He), respectively. There was evidence of inbreeding within populations (Fis = 0.39, 95% CI 0.26–0.55) and significant population differentiation (Fst = 0.16, 0.05–0.24). Analysis of genetic data provided no evidence of isolation by distance, and together with the occurrence of population subdivision, this suggests that there is relatively limited contemporary gene flow among populations. Northern populations of T. erectum tended to have less genetic variability than southern populations, probably as a result of historical factors associated with post glacial migration. Limited opportunities for gene dispersal as a result of low plant densities, the capacity for self-fertilization, and local seed dispersal by ants are likely to be the main factors maintaining contemporary patterns of genetic variation in T. erectum. Key words: allozymes, genetic diversity, gene flow, population genetic structure, Trillium.


2021 ◽  
Author(s):  
◽  
Angel Jimenez Brito

<p>Mugil cephalus is a cosmopolitan fish species found in most coastal waters from tropical to temperate zones. It is a species common in the near-shore marine environment, and known to reside in estuarine and freshwater systems. Adult M. cephalus move out to sea to spawn in aggregations. Their larvae can drift on surface ocean currents for over a month before recruitment to nursery grounds. Mugil cephalus is a species that is closely associated with the coastal environment, but it is capable of interoceanic migrations. Population genetic studies have reported high levels of genetic differentiation among populations in the Mediterranean, Atlantic and western Pacific. However, there is no evidence to suggest reproductive incompatibility has arisen among populations. In New Zealand M. cephalus supports important recreational, commercial and customary fisheries, but very little is known about the distribution and connectivity among populations.  The aim of this study was to use nuclear microsatellite DNA (msatDNA) and mitochondrial DNA (mtDNA) markers to describe the population genetic structure, connectivity patterns and to determine the phylogeographic history of New Zealand M. cephalus populations. Total of 850 samples were collected (576 adults and 274 juveniles) during the summers of 2010 and 2014-2015 from 15 locations around coastal and inland waters of the North Island, and one location in Marlborough Sounds. In addition, 245 mtDNA sequences were added from previously published studies and used to outgroup the New Zealand population and place it into the context of the other Pacific populations.  Seven msatDNA loci were isolated and used to determine the population genetic structure and connectivity patterns of M. cephalus in New Zealand. Admixture of four genetically distinct groups or populations was identified and a chaotic spatial distribution of allele frequencies. Within each population there was significant gene flow among locations, no pattern of genetic isolation-by-distance was identified and there was a high proportion of non-migrant individuals. There was evidence of bottlenecks and seasonal reproductive variation of adults, which could explain the significant shifts in the effective population size among locations.  To test whether the pattern of genetic variation in M. cephalus populations was the result of seasonal variability in the reproductive success of adults, DNA from adult and juvenile samples were used to test for differences in the levels of genetic variation between generations (cohorts). Juveniles were grouped by age classes and compared to the adults. The levels of genetic diversity within the groups of juveniles were compared to the adult population and significant genetic bottlenecks between juveniles and adults were detected. This pattern was consistent with the Sweepstake-Reproductive-Success hypothesis. Two spawning groups in the adults were identified, an early spawning group and a late spawning group.  The analysis of DNA sequence data from the mtDNA Cytochrome Oxidase subunit 1 (COX1) gene and D-loop region showed two sympatric haplogroups of M. cephalus. New Zealand was most likely colonised by M. cephalus migrants from different population sources from the Pacific first ~50,000 and a second wave of migrants from Australia between ~20, 000 and ~16,000 years ago. High levels of gene flow were detected, but there has not been enough time for genetic drift to completely sort the lineages.  The findings of this thesis research will help with the understanding of aspects of M. cephalus dispersal and the genetic structure of populations. The patterns of connectivity can be used to better align the natural boundaries of wild populations to the fishery management stock structure. Understanding the reproductive units, levels of genetic diversity and the patterns of reproduction of M. cephalus will assist management efforts to focus on the key habitats threats, risks and the long-term sustainability of the species.</p>


2020 ◽  
Author(s):  
Cheng Jin ◽  
Huixia Kao ◽  
Shubin Dong

Abstract Background: Studying population genetic structure and gene flow of plant populations and their influencing factors is of particular significance in the field of conservation biology, especially important for species such as rare and endangered plants. Tetraena mongolica Maxim (TM), belongs to Zygophyllaceae family, a rare and endangered plant with narrow distribution. However, for the last decade, due to excessive logging, urban expansion, industrial and tourism development, habitat fragmentation and loss of natural habitats have become major threats to the population of endangered plants. Results: In this study, genetic diversity, population genetic structure and gene flow of TM populations were evaluated by reduced representation sequencing technology, and a total of more than 133.45 GB high-quality clean reads and 38,097 high-quality SNPs were generated. Analysis based on multiple methods, we found that the existing TM populations have moderate levels of genetic diversity , and very low genetic differentiation as well as high levels of gene flow between populations. Population structure and principal coordinates analysis showed that 8 TM populations can be divided into two groups. The Mantel test detected no significant correlation between geographical distances and genetic distance for the whole sampling. Moreover, the migration model indicated that the gene flow is more of an north to south migration pattern in history. Conclusions: This study demonstrates that the present genetic structure is mainly due to habitat fragmentation caused by urban sprawl, industrial development and coal mining. Our recommendation with respect to conservation management is that, all 8 populations should be preserved as a whole population, rather than just those in the core area of TM nature reserve, In particular, the populations near the edge of TM distribution in cities and industrial areas deserve our special protection.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong Wei ◽  
Jiatian Wang ◽  
Zhangyao Song ◽  
Yulan He ◽  
Zihao Zheng ◽  
...  

Abstract Background The Asian tiger mosquito, Aedes albopictus, is one of the 100 worst invasive species in the world and the vector for several arboviruses including dengue, Zika and chikungunya viruses. Understanding the population spatial genetic structure, migration, and gene flow of vector species is critical to effectively preventing and controlling vector-borne diseases. Little is known about the population structure and genetic differentiation of native Ae. albopictus in China. The aim of this study was to examine the patterns of the spatial genetic structures of native Ae. albopictus populations, and their relationship to dengue incidence, on a large geographical scale. Methods During 2016–2018, adult female Ae. albopictus mosquitoes were collected by human landing catch (HLC) or human-bait sweep-net collections in 34 localities across China. Thirteen microsatellite markers were used to examine the patterns of genetic diversity, population structure, and gene flow among native Ae. albopictus populations. The correlation between population genetic indices and dengue incidence was also examined. Results A total of 153 distinct alleles were identified at the 13 microsatellite loci in the tested populations. All loci were polymorphic, with the number of distinct alleles ranging from eight to sixteen. Genetic parameters such as PIC, heterozygosity, allelic richness and fixation index (FST) revealed highly polymorphic markers, high genetic diversity, and low population genetic differentiation. In addition, Bayesian analysis of population structure showed two distinct genetic groups in southern-western and eastern-central-northern China. The Mantel test indicated a positive correlation between genetic distance and geographical distance (R2 = 0.245, P = 0.01). STRUCTURE analysis, PCoA and GLS interpolation analysis indicated that Ae. albopictus populations in China were regionally clustered. Gene flow and relatedness estimates were generally high between populations. We observed no correlation between population genetic indices of microsatellite loci in Ae. albopictus populations and dengue incidence. Conclusion Strong gene flow probably assisted by human activities inhibited population differentiation and promoted genetic diversity among populations of Ae. albopictus. This may represent a potential risk of rapid spread of mosquito-borne diseases. The spatial genetic structure, coupled with the association between genetic indices and dengue incidence, may have important implications for understanding the epidemiology, prevention, and control of vector-borne diseases.


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