Genome survey and microsatellite marker development in the Antarctic Eaton's skate, Bathyraja eatonii (Rajiformes, Arhynchobatidae)

Abstract

Eaton's skate (Bathyraja eatonii) is an endemic Antarctic cartilaginous fish species that primarily inhabits the southern coast of the Antarctic Peninsula and is also distributed across the Kerguelen Plateau near the South Shetland and South Orkney Islands. However, genomic resources for this species remain notably scarce, limiting our understanding of its genetic diversity, population structure, and evolutionary history. To address this knowledge gap, we conducted the first whole-genome survey of B. eatonii. Using 25-mer analysis, we estimated the genome size to be 1.84 Gb, with a heterozygosity rate of 0.26 %. De novo assembly using MaSuRCA yielded over 877,000 scaffolds, with an N50 value of 3572 bp. A total of 1383,652 microsatellite loci were identified, the majority of which were dinucleotide repeats (1163,997; 84.12 %). Among 30 randomly selected primer pairs, 15 consistently produced single, specific amplification bands. These findings provide critical baseline data on the genomic architecture of B. eatonii and represent the first set of molecular markers available for future studies focused on the conservation, evolutionary biology, and population genetics of this species.