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Pinto BJ, Nielsen SV, Sullivan KA, Behere A, Keating SE, van Schingen-Khan M, Nguyen TQ, Ziegler T, Pramuk J, Wilson MA, Gamble T. It's a Trap?! Escape from an ancient, ancestral sex chromosome system and implication of Foxl2 as the putative primary sex determining gene in a lizard (Anguimorpha; Shinisauridae). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.05.547803. [PMID: 37461522 PMCID: PMC10349997 DOI: 10.1101/2023.07.05.547803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Although sex determination is ubiquitous in vertebrates, mechanisms of sex determination vary from environmentally- to genetically-influenced. In vertebrates, genetic sex determination is typically accomplished with sex chromosomes. Groups like mammals maintain conserved sex chromosome systems, while sex chromosomes in most vertebrate clades aren't conserved across similar evolutionary timescales. One group inferred to have an evolutionarily stable mode of sex determination is Anguimorpha, a clade of charismatic taxa including: monitor lizards, Gila monsters, and crocodile lizards. The common ancestor of extant anguimorphs possessed a ZW system that has been retained across the clade. However, the sex chromosome system in the endangered, monotypic family of crocodile lizards (Shinisauridae) has remained elusive. Here, we analyze genomic data to demonstrate that Shinisaurus has replaced the ancestral anguimorph ZW system on LG7 chromosome with a novel ZW system on LG3. The linkage group LG3 corresponds to chromosome 9 in chicken, and this is the first documented use of this syntenic block as a sex chromosome in amniotes. Additionally, this ~1Mb region harbors approximately 10 genes, including a duplication of the sex-determining transcription factor, Foxl2-critical for the determination and maintenance of sexual differentiation in vertebrates, and thus a putative primary sex determining gene for Shinisaurus.
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Affiliation(s)
- Brendan J. Pinto
- School of Life Sciences, Arizona State University, Tempe, AZ USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ USA
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI USA
| | - Stuart V. Nielsen
- Department of Biological Sciences, Museum of Life Sciences, Louisiana State University-Shreveport, Shreveport, LA USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL USA
| | - Kathryn A. Sullivan
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI USA
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
| | - Ashmika Behere
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
| | - Shannon E. Keating
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
| | - Mona van Schingen-Khan
- Federal Agency for Nature Conservation, CITES Scientific Authority, Konstantinstraße 110, 53179 Bonn, Germany
| | - Truong Quang Nguyen
- Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Hanoi 10072, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi 10072, Vietnam
| | - Thomas Ziegler
- Cologne Zoo, Riehler Straße 173, 50735 Cologne, Germany
- Department of Biology, Institute of Zoology, University of Cologne, Zülpicher Straße 47b, 50674 Cologne, Germany
| | | | - Melissa A. Wilson
- School of Life Sciences, Arizona State University, Tempe, AZ USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ USA
- Center for Mechanisms of Evolution, Biodesign Institute, Tempe, AZ USA
| | - Tony Gamble
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI USA
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
- Bell Museum of Natural History, University of Minnesota, St Paul, MN USA
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Pinto BJ, Gamble T, Smith CH, Keating SE, Havird JC, Chiari Y. The revised reference genome of the leopard gecko ( Eublepharis macularius ) provides insight into the considerations of genome phasing and assembly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.523807. [PMID: 36712019 PMCID: PMC9882329 DOI: 10.1101/2023.01.20.523807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Genomic resources across squamate reptiles (lizards and snakes) have lagged behind other vertebrate systems and high-quality reference genomes remain scarce. Of the 23 chromosome-scale reference genomes across the order, only 12 of the ~60 squamate families are represented. Within geckos (infraorder Gekkota), a species-rich clade of lizards, chromosome-level genomes are exceptionally sparse representing only two of the seven extant families. Using the latest advances in genome sequencing and assembly methods, we generated one of the highest quality squamate genomes to date for the leopard gecko, Eublepharis macularius (Eublepharidae). We compared this assembly to the previous, short-read only, E. macularius reference genome published in 2016 and examined potential factors within the assembly influencing contiguity of genome assemblies using PacBio HiFi data. Briefly, the read N50 of the PacBio HiFi reads generated for this study was equal to the contig N50 of the previous E. macularius reference genome at 20.4 kilobases. The HiFi reads were assembled into a total of 132 contigs, which was further scaffolded using HiC data into 75 total sequences representing all 19 chromosomes. We identified that 9 of the 19 chromosomes were assembled as single contigs, while the other 10 chromosomes were each scaffolded together from two or more contigs. We qualitatively identified that percent repeat content within a chromosome broadly affects its assembly contiguity prior to scaffolding. This genome assembly signifies a new age for squamate genomics where high-quality reference genomes rivaling some of the best vertebrate genome assemblies can be generated for a fraction previous cost estimates. This new E. macularius reference assembly is available on NCBI at JAOPLA010000000. The genome version and its associated annotations are also available via this Figshare repository https://doi.org/10.6084/m9.figshare.20069273 .
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Affiliation(s)
- Brendan J. Pinto
- School of Life Sciences, Arizona State University, Tempe, AZ USA
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ USA
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI USA
| | - Tony Gamble
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI USA
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
- Bell Museum of Natural History, University of Minnesota, St Paul, MN USA
| | - Chase H. Smith
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Shannon E. Keating
- Department of Biological Sciences, Marquette University, Milwaukee WI USA
| | - Justin C. Havird
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Ylenia Chiari
- Department of Biology, George Mason University, Fairfax, VA, USA
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