scholarly journals Love the one you’re with: genomic evidence of panmixia in the sablefish (Anoplopoma fimbria)

2017 ◽  
Vol 74 (3) ◽  
pp. 377-387 ◽  
Author(s):  
Andrew J. Jasonowicz ◽  
Frederick W. Goetz ◽  
Giles W. Goetz ◽  
Krista M. Nichols

Understanding the genetic structure of a fishery may help delineate stocks and is directly applicable to resource management. To date, studies have not found clear population genetic structure across the range of the sablefish (Anoplopoma fimbria), yet significant biological differences are recognized. Here we use restriction site-associated DNA sequencing to develop thousands of single nucleotide polymorphisms (SNPs) throughout the sablefish genome and assess population genetic structure and examine the genome for SNPs under natural selection. Our study was unable to target spawning groups, having the potential to bias analyses that require a priori hypotheses of population structure. Low and insignificant levels of differentiation (FST = 0.0002) were observed among survey areas, and analyses of population structure suggested a single population. Only two SNPs were significantly associated with environmental variables. These results are likely due to considerable population mixing and suggest a single panmictic group of sablefish off the west coast of the United States and Alaska that is likely a consequence of a complex juvenile life history and long range movements as adults.

2019 ◽  
Vol 112 (5) ◽  
pp. 2362-2368
Author(s):  
Yan Liu ◽  
Lei Chen ◽  
Xing-Zhi Duan ◽  
Dian-Shu Zhao ◽  
Jing-Tao Sun ◽  
...  

Abstract Deciphering genetic structure and inferring migration routes of insects with high migratory ability have been challenging, due to weak genetic differentiation and limited resolution offered by traditional genotyping methods. Here, we tested the ability of double digest restriction-site associated DNA sequencing (ddRADseq)-based single nucleotide polymorphisms (SNPs) in revealing the population structure relative to 13 microsatellite markers by using four small brown planthopper populations as subjects. Using ddRADseq, we identified 230,000 RAD loci and 5,535 SNP sites, which were present in at least 80% of individuals across the four populations with a minimum sequencing depth of 10. Our results show that this large SNP panel is more powerful than traditional microsatellite markers in revealing fine-scale population structure among the small brown planthopper populations. In contrast to the mixed population structure suggested by microsatellites, discriminant analysis of principal components (DAPC) of the SNP dataset clearly separated the individuals into four geographic populations. Our results also suggest the DAPC analysis is more powerful than the principal component analysis (PCA) in resolving population genetic structure of high migratory taxa, probably due to the advantages of DAPC in using more genetic variation and the discriminant analysis function. Together, these results point to ddRADseq being a promising approach for population genetic and migration studies of small brown planthopper.


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.


2014 ◽  
Vol 10 (8) ◽  
pp. 20140255 ◽  
Author(s):  
Jennifer A. H. Koop ◽  
Karen E. DeMatteo ◽  
Patricia G. Parker ◽  
Noah K. Whiteman

Understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. Co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host–parasite populations. We found that island populations of the Galápagos hawk ( Buteo galapagoensis ) and a parasitic feather louse species ( Degeeriella regalis ) exhibit patterns of co-divergence across variable temporal and spatial scales. Hawks and lice showed nearly identical population genetic structure across the Galápagos Islands. Hawk population genetic structure is explained by isolation by distance among islands. Louse population structure is best explained by hawk population structure, rather than isolation by distance per se , suggesting that lice tightly track the recent population histories of their hosts. Among hawk individuals, louse populations were also highly structured, suggesting that hosts serve as islands for parasites from an evolutionary perspective. Altogether, we found that host and parasite populations may have responded in the same manner to geographical isolation across spatial scales. Allopatric co-divergence is likely one important mechanism driving the diversification of parasites.


2014 ◽  
Vol 51 (4) ◽  
pp. 309-317 ◽  
Author(s):  
O. Zhigileva ◽  
V. Ozhireľev ◽  
T. Stepanova ◽  
T. Moiseenko

AbstractGenetic variability of West Siberian populations of Opisthorchis felineus and two species of cyprinid fish, its second intermediate hosts, was studied by isozyme analysis. Low levels of allozyme variation and genetic differentiation in O. felineus from the Ob-Irtysh focus of opisthorchiasis were detected. The proportion of polymorphic loci was 21.1 %, the average observed heterozygosity (Hobs) was 0.008, and expected heterozygosity (Hexp) was 0.052. For most loci in O. felineus deficit of heterozygotes (FIS = 0.7424) was observed. A comparison of population genetic structure of fish and parasites showed they were not congruent. Estimates of genetic differentiation of the parasite were smaller than for the fish — its intermediate host. Migration and population structure of the second intermediate hosts do not play an important role in formation of the population-genetic structure of O. felineus in the Ob-Irtysh focus of opisthorchiasis.


2018 ◽  
Vol 63 (No. 11) ◽  
pp. 462-472
Author(s):  
Anna Stachurska ◽  
Antoni Brodacki ◽  
Marta Liss

The objective of this study was to estimate the frequencies of alleles which produce coat colour in Polish Coldblood horse population, and to verify the hypothesis that coat colour is not considered in its selection. The analysis included 35 928 horses and their parents having been registered in the studbook over a half-century. Allele frequencies in Agouti (A), Extension (E), Dun (D), Roan (Rn), and Grey (G) loci, in parental and offspring generations, were estimated according to test matings and the square root of recessive phenotype frequency. The population structure is in Hardy–Weinberg equilibrium only at E locus and coat colour is regarded by breeders. Black horses are favoured. Higher E locus homozygosity in blacks than in bays makes it easier to obtain black foals. Dun-diluted, roan and grey coat colours are undesirable and the population has come to consist almost uniformly of basic coat colours. These results show the importance of studies on population genetic structure, which despite no formal criteria for breeding for colour, can considerably change through generations.


2011 ◽  
Vol 62 (1) ◽  
pp. 1 ◽  
Author(s):  
M. C. Sabando ◽  
I. Vila ◽  
R. Peñaloza ◽  
D. Véliz

Dispersal and many other factors affect population genetic structure. In central Chile, rivers are characterised by strong currents and transverse mountain chains, which impose physical barriers to the populations that inhabit them. The objective of the present study was to study the population genetic structure of two widespread species of aquatic insects, the caddisfly Smicridea annulicornis and the mayfly Andesiops torrens, in three isolated rivers, Choapa, Maipo and Maule. The analysis of population structure, using both mtDNA (cytochrome C oxidase subunit 1, COI) and nuclear markers (amplified fragment length polymorphism, AFLP), considered samples from within and among rivers. In S. annulicornis, we found differentiation within and among rivers, indicating a low dispersal among the study area. Populations of A. torrens shared haplotypes in all three rivers and no differences were found among rivers, indicating that this species probably has more dispersal potential than does S. annulicornis; however, significant differences were observed within rivers. Our results indicate that the transverse mountain chains are not a barrier for A. torrens, which can disperse among rivers. Within rivers, the population structure suggests that these species are probably adapted to avoid drift because of the torrential character of these Chilean rivers.


2014 ◽  
Vol 1 (3) ◽  
pp. 140175 ◽  
Author(s):  
Chrysoula Gubili ◽  
David W. Sims ◽  
Ana Veríssimo ◽  
Paolo Domenici ◽  
Jim Ellis ◽  
...  

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark ( Scyliorhinus canicula ), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species.


2000 ◽  
Vol 78 (7) ◽  
pp. 1150-1157 ◽  
Author(s):  
C J Kyle ◽  
C S Davis ◽  
C Strobeck

Elucidating the population genetic structure of a species gives us insight into the levels of gene flow between geographic regions. Such data may have important implications for those trying to manage a heavily harvested wildlife species by determining the genetic connectivity of adjacent populations. In this study, the population structure of 12 North American pine marten (Martes americana) populations from the Yukon through to the central Northwest Territories was investigated using 11 microsatellite loci. Genetic variation within populations across the entire geographic range was relatively homogeneous as measured by: mean number of alleles (5.89 ± 0.45) and the average unbiased expected heterozygosity (He) (65.6 ± 1.7%). The overall unbiased probability of identity showed more variance between populations (1/10.25 ± 7.84 billion) than did the mean number of alleles and the He estimates. Although some population structure was found among the populations, most regions were not strongly differentiated from one another. The low level of structure among the populations can, in part, be attributed to isolation by distance rather than to population fragmentation, as would be expected in more southerly regions in which suitable habitat is more disjunct. Furthermore, the low levels of population genetic structure were likely due to high levels of gene flow between regions and to large effective marten populations in the northern part of their distribution.


2012 ◽  
Vol 7 (5) ◽  
pp. 886-894 ◽  
Author(s):  
Dalius Butkauskas ◽  
Saulius Švažas ◽  
Vaida Tubelytė ◽  
Julius Morkūnas ◽  
Aniolas Sruoga ◽  
...  

AbstractTwo closely related swan species, the mute swan Cygnus olor and the whooper swan Cygnus cygnus, were formerly allopatric throughout their breeding ranges, but during the last decades a sympatric distribution has become characteristic of these species in the Baltic Sea region. The whooper swan has gradually replaced the mute swan in many suitable habitats in Lithuania and Latvia. Marked differences in the genetic population structure of both species may partially explain the dominance of the whooper swan, as genetic population divergence can be a major factor affecting inter-specific competition. A homogenous genetic population structure was defined for mute swans breeding in Lithuania, Latvia, Poland and Belarus. Breeding mute swans in this region are mostly of naturalised origin. A diverse population genetic structure characterizes whooper swans breeding in Lithuania and Latvia.


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