Branchiostoma belcheri & Branchiostoma floridae & Branchiostoma japonicum: Genome sequencing and assembly

The amphioxus, also known as lancelet, is the modern representative of the subphylum Cephalochordata, providing evolutionary insight into the origin of vertebrate. Both amphioxus and vertebrate are evolving relatively slowly, and their genomes share a high level of synteny. The genome of a few species in the genus Branchiostoma have been sequenced: B. floridae, B. belcheri, and B. lanceolatum. However, though amphixous group have retained conserved morphological features for over 100 Myr, the levels of single-nucleotide polymorphisms (SNPs) is very high. Here, we assembled the genomic haplotypes of B. belcheri, B. floridae & B. japonicum, and re-sequenced many individuals to investigate this interest question.

文昌鱼（amphioxus，亦称lancelet）是头索动物亚门（Cephalochordata）的现生代表类群，为解析脊椎动物的起源提供了关键的演化生物学视角。文昌鱼与脊椎动物的演化速率均相对缓慢，二者基因组间具备极高的同线性（synteny）水平。目前，文昌鱼属（Branchiostoma）已有多个物种的基因组完成测序，包括佛罗里达文昌鱼（B. floridae）、贝克氏文昌鱼（B. belcheri）以及矛形文昌鱼（B. lanceolatum）。尽管文昌鱼类群在超过1亿年的演化历程中保留了保守的形态特征，但其单核苷酸多态性（SNPs）水平却极高。本研究组装了贝克氏文昌鱼、佛罗里达文昌鱼与日本文昌鱼（B. japonicum）的基因组单倍型，并对大量个体进行了重测序，以探究这一有趣的科学问题。