scholarly journals Substantial gene flow caused by long‐term translocation between natural bank populations of the Peruvian scallop ( Argopecten purpuratus ) is supported by RAD‐Seq analyses

2021 ◽  
Author(s):  
Ximena Velez‐Zuazo ◽  
Sergio P. Barahona ◽  
Omar G. Melo ◽  
Eric Hanschke ◽  
Ian Hanschke ◽  
...  
Keyword(s):  
Gene Flow ◽  
Argopecten Purpuratus

scholarly journals Substantial gene flow caused by long-term translocation between wild populations of the Peruvian scallop (Argopecten purpuratus) is supported by RAD-Seq analyses

2020 ◽  
Author(s):  
Ximena Velez-Zuazo ◽  
Sergio P. Barahona ◽  
Omar G. Melo ◽  
Eric Hanschke ◽  
Ian Hanschke ◽  
...  
Keyword(s):  
Gene Flow ◽  
Marine Bivalve ◽  
Wild Populations ◽  
Outlier Loci ◽  
Argopecten Purpuratus ◽  
Marine Bivalves ◽  
Genetic Diversity And Structure ◽  
Aquaculture Industry ◽  
Northern Peru

AbstractThe Peruvian scallop (Argopecten purpuratus, Lamarck 1989) is a marine bivalve of high commercial value in the aquaculture industry, with wild populations distributing from northern Peru to Chile. Its growing demand in the world aquaculture markets and limited availability of hatchery-based seeds, caused long-term seed translocations among wild populations to recover depleted local populations and for production needs. We investigated long-term translocations effects on the genetic diversity and structure of wild populations using next-generation RAD sequencing. We sampled individuals from Sechura, Lobos de Tierra, Samanco and Bahia Independencia in Peru, and La Rinconada in Northern Chile. We identified 6275 polymorphic RAD tags and 8345 SNPs for the five populations. We estimated high observed heterozygosity for all populations and high SNP frequency compared to similar studies on marine bivalves. We detected no spatial divergence among populations in Peru (pairwise FST ranged from 0 to 0.003), but strong differentiation with the population in Chile. Migration rate estimates suggested asymmetric directionality of seed translocation. Overall, our results support a remnant effect of an intense historic translocation and on-going gene flow among wild populations in Peru, challenging the identification of outlier loci and certification of sustainable origin of cultured scallops using genetic markers.

Anthropologic Relationships among Prehistoric Northeastern Amerindians

1980 ◽  
Vol 1 (2) ◽  
pp. 145-159
Author(s):  
Edward F. Harris ◽  
Nicholas F. Bellantoni
Keyword(s):  
New York ◽  
Gene Flow ◽  
Material Culture ◽  
New England ◽  
Cultural Barriers ◽  
Group Differences ◽  
Phenetic Analysis ◽  
Trade Relationships ◽  
Good Agreement

Archaeologically defined inter-group differences in the Northeast subarea ate assessed with a phenetic analysis of published craniometric information. Spatial distinctions in the material culture are in good agreement with those defined by the cranial metrics. The fundamental dichotomy, between the Ontario Iroquois and the eastern grouping of New York and New England, suggests a long-term dissociation between these two groups relative to their ecologic adaptations, trade relationships, trait-list associations, and natural and cultural barriers to gene flow.

Population fragmentation causes inadequate gene flow and increases extinction risk

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Extinction Risk ◽  
Random Mating ◽  
Large Population ◽  
Isolated Population ◽  
Population Fragmentation ◽  
Single Population ◽  
Total Size ◽  
Limited Gene Flow

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic diversity, decreased likelihood of evolutionary adaptation and elevated extinction risk, when compared to a single population of the same total size. The consequences of fragmentation with limited gene flow typically lie between those for a large population with random mating and isolated population fragments with no gene flow.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

scholarly journals Expected Genetic Contributions and Their Impact on Gene Flow and Genetic Gain

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 1009-1020 ◽  
Author(s):  
J A Woolliams ◽  
P Bijma ◽  
B Villanueva
Keyword(s):  
Gene Flow ◽  
Genetic Gain ◽  
Overlapping Generations ◽  
Predictive Accuracy ◽  
Index Theory ◽  
Previous Theory ◽  
Selection Indices ◽  
Breeding Groups ◽  
Genetic Contributions

Abstract Long-term genetic contributions (ri) measure lasting gene flow from an individual i. By accounting for linkage disequilibrium generated by selection both within and between breeding groups (categories), assuming the infinitesimal model, a general formula was derived for the expected contribution of ancestor i in category q (μi(q)), given its selective advantages (si(q)). Results were applied to overlapping generations and to a variety of modes of inheritance and selection indices. Genetic gain was related to the covariance between ri and the Mendelian sampling deviation (ai), thereby linking gain to pedigree development. When si(q) includes ai, gain was related to E[μi(q)ai], decomposing it into components attributable to within and between families, within each category, for each element of si(q). The formula for μi(q) was consistent with previous index theory for predicting gain in discrete generations. For overlapping generations, accurate predictions of gene flow were obtained among and within categories in contrast to previous theory that gave qualitative errors among categories and no predictions within. The generation interval was defined as the period for which μi(q), summed over all ancestors born in that period, equaled 1. Predictive accuracy was supported by simulation results for gain and contributions with sib-indices, BLUP selection, and selection with imprinted variation.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

Genetic Differentiation in Isolated Populations of Hakea carinata (Proteaceae)

1998 ◽  
Vol 46 (6) ◽  
pp. 671 ◽  
Author(s):  
G. J. Starr ◽  
S. M. Carthew
Keyword(s):  
Gene Flow ◽  
Habitat Fragmentation ◽  
Gene Diversity ◽  
South Australia ◽  
Similar Species ◽  
Isolated Populations ◽  
Plant Populations ◽  
Evolutionary Condition ◽  
Private Alleles

Fragmentation of the landscape by human activity has created small, isolated plant populations. Hakea carinata F. Muell. ex Meissner, a sclerophyllous shrub, is common in isolated fragments of vegetation in South Australia. This study investigated whether habitat fragmentation has caused restrictions to gene flow between populations. Gene diversity (HT = 0.317) is average for similar species but little is held within populations (HS = 0.168) and 46.9% of gene diversity is accounted for between populations. Estimates of gene flow are NM = 0.270 (based on FST) and NM = 0.129 (based on private alleles). Populations are substantially selfing (t = 0.111). Small isolated populations appears to be a long-term evolutionary condition in this species rather than a consequence of habitat fragmentation; however, population extinctions are occurring. Conservation will require the reservation of many populations to represent the genetic variation present in the species.

scholarly journals Long-Term Reciprocal Gene Flow in Wild and Domestic Geese Reveals Complex Domestication History

2020 ◽  
Vol 10 (9) ◽  
pp. 3061-3070 ◽  
Author(s):  
Marja E Heikkinen ◽  
Minna Ruokonen ◽  
Thomas A White ◽  
Michelle M Alexander ◽  
İslam Gündüz ◽  
...  
Keyword(s):  
Gene Flow ◽  
Wild Form ◽  
Nucleotide Polymorphisms ◽  
Anser Anser ◽  
Domestic Species ◽  
Genome Wide ◽  
Domestication Process ◽  
Historical Writings ◽  
The Impact

Abstract Hybridization has frequently been observed between wild and domestic species and can substantially impact genetic diversity of both counterparts. Geese show some of the highest levels of interspecific hybridization across all bird orders, and two of the goose species in the genus Anser have been domesticated providing an excellent opportunity for a joint study of domestication and hybridization. Until now, knowledge of the details of the goose domestication process has come from archaeological findings and historical writings supplemented with a few studies based on mitochondrial DNA. Here, we used genome-wide markers to make the first genome-based inference of the timing of European goose domestication. We also analyzed the impact of hybridization on the genome-wide genetic variation in current populations of the European domestic goose and its wild progenitor: the graylag goose (Anser anser). Our dataset consisted of 58 wild graylags sampled around Eurasia and 75 domestic geese representing 14 breeds genotyped for 33,527 single nucleotide polymorphisms. Demographic reconstruction and clustering analysis suggested that divergence between wild and domestic geese around 5,300 generations ago was followed by long-term genetic exchange, and that graylag populations have 3.2–58.0% admixture proportions with domestic geese, with distinct geographic patterns. Surprisingly, many modern European breeds share considerable (> 10%) ancestry with the Chinese domestic geese that is derived from the swan goose Anser cygnoid. We show that the domestication process can progress despite continued and pervasive gene flow from the wild form.

Weak genetic structuring suggests historically high genetic connectivity among recently fragmented urban populations of the scincid lizard, Ctenotus fallens

2015 ◽  
Vol 63 (4) ◽  
pp. 279 ◽  
Author(s):  
Josef Krawiec ◽  
Siegfried L. Krauss ◽  
Robert A. Davis ◽  
Peter B. S. Spencer
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Large Population ◽  
Geographic Distance ◽  
Genetic Erosion ◽  
Genetic Connectivity ◽  
Genetic Structuring ◽  
Low Genetic Diversity ◽  
Population Sizes

Populations in fragmented urban remnants may be at risk of genetic erosion as a result of reduced gene flow and elevated levels of inbreeding. This may have serious genetic implications for the long-term viability of remnant populations, in addition to the more immediate pressures caused by urbanisation. The population genetic structure of the generalist skink Ctenotus fallens was examined using nine microsatellite markers within and among natural vegetation remnants within a highly fragmented urban matrix in the Perth metropolitan area in Western Australia. These data were compared with samples from a large unfragmented site on the edge of the urban area. Overall, estimates of genetic diversity and inbreeding within all populations were similar and low. Weak genetic differentiation, and a significant association between geographic and genetic distance, suggests historically strong genetic connectivity that decreases with geographic distance. Due to recent fragmentation, and genetic inertia associated with low genetic diversity and large population sizes, it is not possible from these data to infer current genetic connectivity levels. However, the historically high levels of gene flow that our data suggest indicate that a reduction in contemporary connectivity due to fragmentation in C. fallens is likely to result in negative genetic consequences in the longer term.

Genetic contributions of Finnish Ayrshire bulls over four generations

1995 ◽  
Vol 61 (2) ◽  
pp. 177-187 ◽  
Author(s):  
J. A. Woolliams ◽  
E. A. Mäntysaari
Keyword(s):  
Gene Flow ◽  
Genetic Relationship ◽  
Artificial Insemination ◽  
Pedigree Information ◽  
Generation Interval ◽  
New Information ◽  
Genetic Contributions ◽  
Additive Genetic Relationship

AbstractThe long-term genetic contributions were calculated for 219 Finnish Ayrshire bulls born between 1958 and 1964 to 707 Finnish Ayrshire bulls made available for artificial insemination and born between 1986 and 1988. Three strategies were employed:(i) using all known pedigree information; (ii) ignoring information on the dam of females; (iii) only using information on sires. Expected contributions were calculated using gene flow matrices.The contributions from strategies 1, 2 and 3 were only 0.6 (1 and 2) or 0.7 (strategy 3) of those expected. The causes of this shortfall for strategies 2 and 3 were identified as (i) the use of an imported sire and (ii) generation skipping. For strategy 1, 0.2 of the expected pathways remained unaccounted for and were ascribed to missing pedigree information.Of the 219 ancestors, only 86 made positive contributions to the descendants. Only 10 ancestors made contributions more than the average, and one bull accounted for 0.3 of all pathways traced on strategy 2. There was general agreement in the relative contributions of individual bulls when assessed using the three strategies.The rate of inbreeding (ΔF) estimated by regression from 1974 to 1988 and using known pedigrees was 0.0018 per year and the average coefficients of additive genetic relationship among cohorts was increasing by 0.0030 per year. AF was estimated using the contributions calculated by strategies 1, 2 and 3 to be 0.0147, 0.0151 and 0.0125 per generation respectively. These were converted into rates per year by assuming a generation interval of 6.5 years taken from both published and new information on generation intervals in the Finnish Ayrshire population. This gave annual rates of 0.0023, 0.0023 and 0.0019. The estimates from strategy 3 were obtained without the use of any pedigree information pertaining to dams.

Sign in / Sign up

Export Citation Format

Share Document