Identification And Evolutionary Analysis Of The Keratinizing ? Protein Gene Family In Gecko Verrucas

During the adaptive evolution of vertebrates from aquatic to terrestrial ecosystems,the evolution of epidermis played an important role in preventing mechanical damage and water loss in vertebrates.The epidermis and its appendages such as feathers,claws,scales and so on are mainly composed of corneous beta proteins(CBPs),once known as "?-keratin".These proteins are encoded by members of the CBP gene family and are found only in sauroids(birds and reptiles).Although the CBP gene family of Gekko japonicus had been identified,the localization of which is not clear due to the limitation of the genome assembly quality of Gekko japonicus.Therefore,in this study,the genome of the Gekko japonicus was assembled into 19 chromosomes by using the thirdgeneration sequencing(TGS)technology and the high-through chromosome conformation capture(Hi-C)technology.The genome assembly is 2.51 Gbp with an N50 contig length of 2.08 Mbp and an N50 scaffold length of 172.24 Mb.Repeat elements make up 69.43% of the genome and non-protein-coding RNA families make up 0.17% of it.A total of 20,503 genes were annotated,96.49% of which were annotated to be functional.Compared with the last version of the Gekko japonicus genome,the latest version is of better quality.The synteny analysis shows that chromosome rupture and recombination events may have happened in the genome of Gekko japonicus.1,106 single-copy homologous gene families are shared among the21 species through gene family cluster analysis.There are a total of 13,930 gene families and 114 unique ones in Gekko japonicus,with an average of 1.33 genes in each gene family.Phylogenetic analyses indicate that the Gekko japonicus lineage diverged from that of snakes and lizards around 191.9 million years ago.Expansion and contraction analysis of gene families showed that the most recent common ancestor of these 21 species had a total of 21,570 gene families.In this study,66 members of the CBP gene family of Gekko japonicus were identified by BLASTP,using high assembly quality genome of Gekko japonicus,revealing the chromosomal localization of the CBP gene family and the synteny relationship among the CBP gene family of the species.