Serranito, B. | Search bioRxiv

bioRxiv2026

Mitochondrial DNA haplotypes reveal a fine-scale population structure in sperm whales (Physeter macrocephalus) around Sao Miguel Island (Azores)

The sperm whale is an emblematic species of the Azores archipelago. After a century of intensive whaling, the species has become a focal point for ecotourism since the late 1980s, enabling collaborative research during tourism activities. This study assessed the feasibility of using a citizen science based non-invasive sampling approach to evaluate the genetic diversity of local sperm whales. Seven local whale-watching companies contributed to collect 70 fecal samples and 34 sloughed skin fragments between 2019 and 2024. A 588-bp fragment of mitochondrial DNA Control Region (MCR) was successfully sequenced from 56 fecal samples and all skin fragments, yielding 90 MCR sequences assigned to 79 individual sperm whales. MCR sequences from both sources of the same individuals were in perfect agreement, validating the use of fecal samples for mitochondrial haplotype analysis - the first study to do so in sperm whales. Four MCR haplotypes, including a newly determined one, evidenced different maternal lineages within the Macaronesia population. Haplotypes showed a clear geographic pattern around Sao Miguel Island: one was restricted almost exclusively to the south coast, while the other three occurred predominantly on the north. This contrasted distribution is likely correlated to different matrilineal groups.

ecology↗

bioRxiv2021

Local adaptations of Mediterranean sheep and goats through an integrative approach

In a context of climate change, identifying the genes underlying adaptations to extreme environments is essential. Small ruminants are adapted to a wide variety of habitats and thus, are promising study models. Here, we considered 17 goat and 25 sheep local Mediterranean breeds, in Italy, France and Spain. We proposed, and empirically tested a new methodology to highlight selection signatures in relation to the environments. Based on historical archives, we selected the breeds potentially most linked to a territory and defined their original geographical cradle, including transhumant pastoral areas. For both species, the cradles were arranged along latitudinal gradient of aridity and altitude. Then we used the programs PCAdapt and LFMM. Considering cradles, instead of current GPS coordinates, markedly improved the sensitivity of the LFMM analyses. All the results combined with a systematic literature review, revealed a set of genes with potentially key adaptive roles. Some of these genes, have been found implicated in lipid metabolism (SUCLG2, BMP2), hypoxia/heat stress (UBE2R2/UBAP2), lung function (BMPR2), seasonal patterns (SOX2, DPH6) or neuronal function (TRPC4, TRPC6). For the intergenic region between PCDH9 and KLH1, as well as NBEA, identified in both species, the adaptive role could be strong. We found for RXFP2, associated with sheep horn development, and MSRB3 and SLC26A4, both associated with hearing of sheep, a strong association with the environment gradient. We conclude that our new methodology, which considers breeds in their historical, environmental and anthropological context, provides novel and essential information on local breeds and their unique adaptations.

evolutionary biology↗