Genetic diversity and structure of blue whales (Balaenoptera musculus) in Australian feeding aggregations

Knowledge of genetic diversity and structure is essential for developing conservation strategies for endangered species. The advances in museum genomics can assist in better understanding the effects of over-hunting on the genome by comparing historical to present-day samples. Blue whales were hunted to the point of near extinction in the mid-twentieth century. Herein, we use whole genome sequencing to elucidate the poorly understood population structure of North Atlantic (NA) blue whales (Balaenoptera musculus musculus). We generated a de novo genome assembly of 2.49 Mbp for a NA blue whale (N50 of 1.46 Mb) to analyze 19 whole genomic sequences and 28 complete mitochondrial genomes. We included present-day and historical samples (earliest from 1900) from the Atlantic and Antarctica to understand the impact of whaling on the genetic diversity. We found low population structuring, but high genetic diversity, suggesting a single, panmictic population in the NA. We identified gene flow from fin whale to blue whales, accounting for ~3.5% of the genome. Introgression between blue and fin whales was observed in all the present-day samples but were lacking in some whales sampled early in the 20th century, which suggests increasing disruption in mate choice concomitant with decline in blue whale population. We also assembled and analyzed the transcriptome and revealed positive selection of oncogenes, which may be involved in reduced cancer rates in this largest of mammals ever known. Our sequencing and population structuring studies provide a genomic framework to guide ongoing conservation strategies for this iconic species.

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Low genetic diversity in pygmy blue whales is due to climate-induced diversification rather than anthropogenic impacts

Biology Letters ◽

10.1098/rsbl.2014.1037 ◽

2015 ◽

Vol 11 (5) ◽

pp. 20141037 ◽

Cited By ~ 10

Author(s):

Catherine R. M. Attard ◽

Luciano B. Beheregaray ◽

K. Curt S. Jenner ◽

Peter C. Gill ◽

Micheline-Nicole M. Jenner ◽

...

Keyword(s):

Climate Change ◽

Genetic Diversity ◽

Anthropogenic Impacts ◽

Future Climate Change ◽

Evolutionary Divergence ◽

Balaenoptera Musculus ◽

Low Genetic Diversity ◽

Low Levels ◽

Analytical Approaches ◽

Blue Whales

Unusually low genetic diversity can be a warning of an urgent need to mitigate causative anthropogenic activities. However, current low levels of genetic diversity in a population could also be due to natural historical events, including recent evolutionary divergence, or long-term persistence at a small population size. Here, we determine whether the relatively low genetic diversity of pygmy blue whales ( Balaenoptera musculus brevicauda ) in Australia is due to natural causes or overexploitation. We apply recently developed analytical approaches in the largest genetic dataset ever compiled to study blue whales (297 samples collected after whaling and representing lineages from Australia, Antarctica and Chile). We find that low levels of genetic diversity in Australia are due to a natural founder event from Antarctic blue whales ( Balaenoptera musculus intermedia ) that occurred around the Last Glacial Maximum, followed by evolutionary divergence. Historical climate change has therefore driven the evolution of blue whales into genetically, phenotypically and behaviourally distinct lineages that will likely be influenced by future climate change.

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Genetic diversity and population structure of Plasmodium falciparum in Nigeria: insights from microsatellite loci analysis

Malaria Journal ◽

10.1186/s12936-021-03734-x ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Fehintola V. Ajogbasile ◽

Adeyemi T. Kayode ◽

Paul E. Oluniyi ◽

Kazeem O. Akano ◽

Jessica N. Uwanibe ◽

...

Keyword(s):

Genetic Diversity ◽

Plasmodium Falciparum ◽

Population Structure ◽

Microsatellite Loci ◽

Control Strategies ◽

Population Diversity ◽

Parasite Population ◽

Nested Polymerase Chain Reaction ◽

Public Health Burden ◽

Genetic Diversity And Structure

Abstract Background Malaria remains a public health burden especially in Nigeria. To develop new malaria control and elimination strategies or refine existing ones, understanding parasite population diversity and transmission patterns is crucial. Methods In this study, characterization of the parasite diversity and structure of Plasmodium falciparum isolates from 633 dried blood spot samples in Nigeria was carried out using 12 microsatellite loci of P. falciparum. These microsatellite loci were amplified via semi-nested polymerase chain reaction (PCR) and fragments were analysed using population genetic tools. Results Estimates of parasite genetic diversity, such as mean number of different alleles (13.52), effective alleles (7.13), allelic richness (11.15) and expected heterozygosity (0.804), were high. Overall linkage disequilibrium was weak (0.006, P < 0.001). Parasite population structure was low (Fst: 0.008–0.105, AMOVA: 0.039). Conclusion The high level of parasite genetic diversity and low population structuring in this study suggests that parasite populations circulating in Nigeria are homogenous. However, higher resolution methods, such as the 24 SNP barcode and whole genome sequencing, may capture more specific parasite genetic signatures circulating in the country. The results obtained can be used as a baseline for parasite genetic diversity and structure, aiding in the formulation of appropriate therapeutic and control strategies in Nigeria.

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