Gene flow prevents genetic diversity loss despite small effective population size in fragmented grizzly bear (Ursus arctos) populations

Conservation Genetics, Год журнала: 2024, Номер unknown

Опубликована: Дек. 25, 2024

Abstract Genetic monitoring is important in small, fragmented populations that rely on gene flow to maintain genetic diversity. The Selkirk, Yaak, and Cabinet grizzly bear ( Ursus arctos ) are among the smallest North America near southernmost extent of species’ range. These received little no effective migration for generations but have recently experienced increased through natural a population augmentation program. A long-term dataset microsatellite genotypes from 1973 2021 presented unique opportunity examine trends these over time. We used this 464 bears evaluate if affected observed heterozygosity H O ), expected E allelic richness R average pairwise relatedness r each populations. also estimated size N e using temporal linkage disequilibrium (LD) methods. Post flow, Selkirk decreased all three did not observe any significant changes or , values our were significantly higher than those model without flow. Our estimates consistent between LD methods ranged 15.2 15.8, 15.4–17.5, 5.6–8.9 populations, respectively. Overall, findings indicate increasing maintaining diversity However, remains low additional connectivity may be needed, particularly population.

Язык: Английский

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Gene flow accelerates adaptation to a parasite

Evolution, Год журнала: 2023, Номер 77(6), С. 1468 - 1478

Опубликована: Март 22, 2023

Abstract Gene flow into populations can increase additive genetic variation and introduce novel beneficial alleles, thus facilitating adaptation. However, gene may also impede adaptation by disrupting genotypes, introducing deleterious or creating dominant negative interactions. While theory fieldwork have provided insight the effects of flow, direct experimental tests are rare. Here, we evaluated on in nematode Caenorhabditis elegans during exposure to bacterial parasite, Serratia marcescens. We evolved hosts against nonevolving parasites for 10 passages while controlling host source population. used with three different backgrounds (one similar sink population two different) evolutionary histories (previously adapted S. marcescens naive). found that exhibited greater increases parasite resistance than those without flow. Additionally, from resulted naive populations, particularly backgrounds. Overall, this work demonstrates facilitate suggests architecture history alter population’s response selection.

Язык: Английский

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Genomic-guided conservation actions to restore the most endangered conifer in the Mediterranean Basin

bioRxiv (Cold Spring Harbor Laboratory), Год журнала: 2023, Номер unknown

Опубликована: Ноя. 25, 2023

Abstract Species with extremely small population sizes are critically endangered due to reduced genetic diversity, increased inbreeding, and the added threat of hybridization. Genomic tools significantly advance conservation by revealing insights into species, notably in monitoring frameworks. Sicilian fir is most conifer Europe only 30 adult trees spread across an 84-hectare area. Using 20,824 SNPs from RAD-seq employing silver genome assembly a custom 120 SNP-array, we evaluated mating patterns, effective size trees, 118 natural seedlings, 2,064 nursery seedlings past actions. We assessed introgression neighboring non-native plantations established intra-population assisted gene flow program selecting genetically dissimilar individuals investigating outcome through simulations. analysis unveiled significant diversity among firs, comparable non-endangered Mediterranean firs larger populations. However, forthcoming generation declined high self-fertilization, leading marked inbreeding (Fis = 0.38) alarmingly low ( N e 6). Nursery seedling revealed similar selfing rates but (∼50%) firs. Although could help mitigate loss, it may not alleviate species vulnerability imminent environmental challenges, perpetuating risk extinction vortex. Hence, impact decline on depression, along exploring potential hybrids for load alleviation future adaptation, crucial strategies. This study stands as compelling model guiding strategies similarly imperiled characterized

Язык: Английский

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Outbreeding management offers the promise of genetic rescue for an endangered lizard

Current Zoology, Год журнала: 2024, Номер 70(6), С. 721 - 727

Опубликована: Фев. 27, 2024

Abstract Inbreeding and loss of genetic diversity increase the extinction risk small isolated populations. Genetic rescue by augmenting gene flow is a powerful means for restoration lost variation. In this study, we used multigenerational pedigrees neutral markers to assess consequences outbreeding management in Chinese Vietnamese populations endangered crocodile lizard, Shinisaurus crocodilurus. Compared with purebred population, population exhibited greater molecular variation 3-fold larger size. Moreover, first-generation hybrids had longer lifespan than purebreds, suggesting that depression did not occur, but long-term fitness effect needs be further evaluated. Our study provides valuable insights into potential emphasizing importance an evidence-based approach address risks inbreeding threatened

Язык: Английский

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Genetic variation and hybridization determine the outcomes of conservation reintroductions

Conservation Letters, Год журнала: 2024, Номер unknown

Опубликована: Сен. 4, 2024

Abstract The preservation of genetic variation is fundamental in biodiversity conservation, yet its importance for population viability remains contentious. Mixed‐source reintroductions, where individuals are translocated into a single vacant habitat from multiple genetically divergent and often depauperate populations, provide an opportunity to evaluate how hybridization influence individual relative fitness. Population theory predicts that with higher hybrids among populations should have We tested these two hypotheses by analyzing population‐scale data westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) four mixed‐source reintroductions. observed more hybrid fewer nonhybrid offspring than expected across independent also found clear evidence heterozygosity influenced reproductive Overall, we strong, positive relationship between variation, hybridization, transplant fitness, emphasizing the mixing conservation.

Язык: Английский

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Comparing the ecological consequences of globally invasive fishes versus their F1 hybrids in recreational fisheries

NeoBiota, Год журнала: 2024, Номер 95, С. 267 - 278

Опубликована: Окт. 14, 2024

Recreational angling is a major introduction pathway for non-native fish into freshwaters, where multiple fishes are often released waterbodies to diversify the opportunities. When these taxonomically similar, then there concern that their hybridisation will result in F1 generations comprising of novel phenotypes outperform parental species, resulting impacts ecological engineering species being accelerated. Across two water temperatures (18 °C, 26 °C), comparative functional response analyses (CFR) quantified consumption patterns globally invasive freshwater common carp Cyprinus carpio and goldfish Carassius auratus , plus hybrids, before testing differences specific growth rates (SGRs). In CFRs, consumed significantly more prey at 18 °C than other fishes, with no between any °C. SGRs also did not differ substantially either temperature. These results suggest high impacting produce performance could accelerate invaded ecosystems. Accordingly, risks use recreational remain an issue primarily associated parent populations, this can be reflected invasion management.

Язык: Английский

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ddRAD-seq reveals conservation units and signatures of local adaptation in wild Nile tilapia populations of Ethiopia

Hydrobiologia, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 14, 2024

Язык: Английский

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The Effects of Hybridization and Parasite Infection on the Survival and Behaviour of Endangered Landlocked Salmon Subject to Predation—Implications for Genetic Rescue

Evolutionary Applications, Год журнала: 2024, Номер 17(12)

Опубликована: Дек. 1, 2024

ABSTRACT A prerequisite of genetic rescue in endangered and genetically depauperate populations is to pre‐evaluate between possible pros cons hybridization for the life history survival target population. We hybridized critically Saimaa landlocked salmon ( Salmo salar m. sebago ) with one its geographically closest relatives, anadromous Baltic from River Kymijoki. In two similar experiments, conducted semi‐natural streams during overwintering (at age 1.5) early summer (age 2+), we studied how eye parasite infection Diplostomum pseudospathaceum affected predation by Northern pike Esox lucius ). Additionally, recorded movements juvenile using passive integrated telemetry gain insights into effect on antipredatory behaviour (movement activity habitat use). Among uninfected groups, found significantly lower mortality hybrid (mortality ± S.E. 14.5% 5.4%) compared purebred (37.2% 9.4%), supporting a positive under risk. This benefit, however, was cancelled out infection, which impaired vision increased susceptibility predation. The negative effects were particularly pronounced due resistance, salmon. Hybridization per se did not affect levels salmon, but correlated positively cataract coverage, highest These results demonstrate that controlled supplementation small animal population more diverse hybrids could entail both implications, at least first crossbred generation.

Язык: Английский

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Genome assisted gene-flow rescued genetic diversity without hindering growth performance of inbred coho salmon (Oncorhynchus kisutch) population selected for high growth phenotype

Research Square (Research Square), Год журнала: 2024, Номер unknown

Опубликована: Дек. 17, 2024

Selective breeding is a powerful tool for improving aquaculture production. A well-managed program essential, as populations can otherwise lose genetic diversity, leading to reduced selection response and inbreeding excesses. In such cases, diversity in broodstock must be restored by introducing individuals from external populations. However, this reduce the accumulated gains selective breeding. On other hand, selectively introduction of with superior phenotypes will allow restoration without sacrificing these gains. study, we demonstrated possibility using bred (SB) randomly (RB) population coho salmon (Oncorhynchus kisutch). Forty males growth were selected RB genomic crossed 127 collected females SB produce newly (NB) population. Genetic assessed statistics effective number alleles, allele richness, observed heterozygosity 11 microsatellite markers, was higher NB than RB. Additionally, folk length body weight compared among three after 12-month communal culture fertilization. The least-squares means similar between (164.9 mm 57.9 g) (161.1 53.7 g), while both significantly larger those (150.4 43.0 g). Our results highlight effectiveness genome-assisted gene flow restoring compromising their gain growth.

Язык: Английский

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