Biology subjects

Ruzzante, D. E.

Publications and source records attributed to Ruzzante, D. E..

3 recordsLinked to original sources

bioRxiv2023

Global assessment of effective population sizes: consistent taxonomic differences in meeting the 50/500 rule

Effective population size (Ne) is a particularly useful metric for conservation as it affects genetic drift, inbreeding and adaptive potential within populations. Current guidelines recommend a minimum Ne of 50 and 500 to avoid short-term inbreeding and to preserve long-term adaptive potential, respectively. However, the extent to which wild populations reach these thresholds globally has not been investigated, nor has the relationship between Ne and human activities. Through a quantitative review, we generated a dataset with 4145 georeferenced Ne estimates from 3576 unique populations, extracted from 712 articles. These data show that certain taxonomic groups are less likely to meet 50/500 thresholds and are disproportionately impacted by human activities; plant, mammal, and amphibian populations had a [≤]52% probability of reaching[N] e = 50 and a <5% probability of reaching[N] e = 500. Populations listed as being of conservation concern according to the IUCN Red List had a lower[N] e than unlisted populations, and this relationship held true across all taxonomic groups.[N] e was reduced in areas with a greater Global Human Footprint, especially for amphibians and mammals, however relationships varied between taxa. We also highlight several considerations for future works estimating[N] e, including the role that gene flow and subpopulation structure plays in the estimation of[N] e in wild populations, and the need for finer-scale taxonomic analyses. Our findings provide guidance for more specific thresholds based on Ne and help prioritize assessment of populations from taxa most at risk of failing to meet conservation thresholds.

evolutionary biology↗

bioRxiv2019

Adaptation to seasonal reproduction and thermal minima-related factors drives fine-scale divergence despite gene flow in Atlantic herring populations

Natural selection can maintain local adaptation despite the presence of gene flow. However, the genomic basis and environmental factors involved in adaptation at fine-spatial scales are not well understood. Here, we address these questions using Atlantic herring (Clupea harengus), an abundant, migratory, and widely distributed marine species with substantial genomic resources including a chromosome-level genome assembly and genomic data from the eastern Atlantic and Baltic populations. We analysed whole-genome sequence and oceanographic data to examine the genetic variation of 15 spawning aggregations across the northwest Atlantic Ocean ([~]1,600 km of coastline) and the association of this variation with environmental variables. We found that population structure lies in a small fraction of the genome involving adaptive genetic variants of functional importance. We discovered 10 highly differentiated genomic regions distributed across four chromosomes. Two of these loci appear to be private to the northwest, four loci share a large number of adaptive variants between northwest and northeast Atlantic, and four shared loci exhibit an outstanding diversity in haplotype composition, including a novel putative inversion on chromosome 8. Another inversion on chromosome 12 underlies a latitudinal genetic pattern discriminating populations north and south of a biogeographic transition zone on the Scotian Shelf. Our genome-environment association analysis indicates that sea water temperature during winter is the environmental factor that best correlates with the latitudinal pattern of this inversion. We conclude that the timing and geographic location of spawning and early development are under diverse selective pressures related to environmental gradients. Natural selection appears to act on early-life performance traits with differential fitness across environments. Our study highlights the role of genomic architecture, ancestral haplotypes, and selection in maintaining adaptive divergence in species with large population sizes and presumably high gene flow.

genomics↗

bioRxiv2018

Extensive Secondary Contact Among Three Glacial Lineages of Arctic Char (Salvelinus alpinus) in Newfoundland and Labrador

We sequenced a portion of the D-loop region in over 1000 Arctic char (Salvelinus alpinus) samples from 67 locations across Newfoundland and Labrador to assess the extent of secondary contact among the Arctic, Atlantic, and Acadian glacial lineages in Newfoundland and Labrador. Within Labrador, the Arctic and Atlantic lineages were widespread. Two locations (one landlocked and one with access to the sea) also contained individuals of the Acadian lineage, constituting the first record of this lineage in Labrador. Atlantic and Acadian lineage individuals were found in both eastern and western Newfoundland. Multiple sampling locations in Newfoundland and Labrador contained fish of two or more different glacial lineages, implying their introgression. Glacial lineage did not appear to dictate contemporary genetic divergence between the pale and dark morph of char present in Gander Lake, Newfoundland. Both were predominately of the Atlantic lineage, suggesting the potential for their divergence in sympatry. This study reveals Newfoundland and Labrador to be a unique junction of three glacial lineages which have likely hybridized extensively in this region.

evolutionary biology↗