High-quality reference genome of the African hermit spider, Nephilingis cruentata, and sex chromosome evolution in spiders
Background: Chromosome-level genome assemblies are increasingly enabling tests of chromosome evolution, conserved synteny, and sex chromosome conservation across diverse animal lineages, including spiders. Results: Here, we present a chromosome-level genome assembly for the African hermit spider, Nephilingis cruentata, a species with extreme female-biased sexual size dimorphism and a…
Chromosome-level genome of African hermit spider published, sheds light on sex chromosome evolution
Scientists have released a chromosome-level genome assembly for the African hermit spider, Nephilingis cruentata. This species exhibits extreme female-biased sexual size dimorphism and a sex chromosome system inferred from cytogenetic data as XX2. The final assembly spans 1.72 Gbp, assigning 99.5% of the genome to 13 pseudochromosomes. With an N50 of 131.6 Mbp and a BUSCO completeness score of 98.8%, the assembly includes 20,021 protein-coding genes. The repetitive elements make up 42.7% of the genome.
Through sex-specific whole-genome resequencing, researchers identified Chr02 and Chr07 as candidate X chromosomes, aligning with the expected XX2 system. By comparing the genome to existing chromosome-scale assemblies of spiders, the study found that sex-linked chromosomes maintain broad homologous identity across various spider lineages.
However, these chromosomes show lower synteny conservation and greater chromosome-length divergence compared to autosomes. These findings suggest that spider sex chromosomes are conserved in terms of homologous identity but exhibit greater structural variability, providing a comparative framework for studying sex chromosome conservation and divergence among Araneae.
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