Mollusca is the second most species-rich phylum and includes animals as disparate as octopuses, clams, and chitons. Dozens of molluscan genomes are available, but only one representative of the subphylum Aculifera, the sister taxon to all other molluscs, has been sequenced to date, hindering comparative and evolutionary studies. To facilitate evolutionary studies across Mollusca, we sequenced the genome of a second aculiferan mollusc, the lepidopleurid chiton Hanleya hanleyi (Bean 1844), using a hybrid approach combining Oxford Nanopore and Illumina reads. After purging redundant haplotigs and removing contamination from this 1.3% heterozygous genome, we produced a 2.5 Gbp haploid assembly (>4X the size of the other chiton genome sequenced to date) with an N50 of 65.0 Kbp. Despite a fragmented assembly, the genome is rather complete (92.0% of BUSCOs detected; 79.4% complete plus 12.6% fragmented). Remarkably, the genome has the highest repeat content of any molluscan genome reported to date (>66%). Our gene annotation pipeline predicted 69,284 gene models (92.9% of BUSCOs detected; 81.8% complete plus 11.1% fragmented) of which 35,362 were supported by transcriptome and/or protein evidence. Phylogenomic analysis recovered Polyplacophora sister to all other sampled molluscs with maximal support. The Hanleya genome will be a valuable resource for studies of molluscan biology with diverse potential applications ranging from evolutionary and comparative genomics to molecular ecology.
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Two draft genomes of enigmatic Solenogastres (Mollusca, Aplacophora) Epimenia babai and Neomenia megatrapezata
Many molluscan genomes have been published to date, however only three are from representatives of the subphylum Aculifera (Polyplacophora, Caudofoveata, and Solenogastres), the sister taxon to all other molluscs. Currently, genomic resources are completely lacking for Solenogastres. This gap in knowledge hinders comparative and evolutionary studies. Here, we sequenced the genomes of the solenogaster aplacophoransEpimenia babai Salvini-Plawen, 1997 andNeomenia megatrapezata Salvini-Plawen & Paar-Gausch, 2004 using a hybrid approach combining Oxford Nanopore and Illumina reads. ForE. babai , we produced a 628 Mbp haploid assembly (N50 = 413 Kbp, L50 = 370) that is rather complete with a BUSCO completeness score of 90.1% (82.0% single, 8.1% duplicated, 6.0% fragmented, and 3.9% missing). ForN. megatrapezata , we produced a 412 Mbp haploid assembly (N50 = 132 Kbp, L50 = 881) that is also rather complete with a BUSCO completeness score of 85.1% (81.7% single, 3.4% duplicated, 8.1% fragmented, and 6.8% missing). Our annotation pipeline predicted 25,393 gene models forE. babai with a BUSCO score of 92.4% (80.5% single, 11.9% duplicated, 4.9% fragmented, and 2.7% missing) and 22,463 gene models forN. megatrapezata with a BUSCO score of 90.2% (81.0% single, 9.2% duplicated, 4.7% fragmented, and 5.1% missing). Phylogenomic analysis recovered Solenogastres as the sister taxon to Polyplacophora and Aculifera as the sister taxon to all other sampled molluscs with maximal support. These represent the first whole-genome resources for Solenogastres and will be valuable for future studies investigating this understudied group and molluscan evolution as a whole.
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- Award ID(s):
- 1846174
- PAR ID:
- 10538377
- Publisher / Repository:
- F1000 Research Ltd.
- Date Published:
- Journal Name:
- F1000Research
- Volume:
- 13
- ISSN:
- 2046-1402
- Page Range / eLocation ID:
- 318
- Subject(s) / Keyword(s):
- Aculifera Aplacophora Solenogastres genome
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.12688/f1000research.148511.1
