Branchiostoma Belcheri BAC Sequencing And Comparative Genomics Analysis

The cephalochordate amphioxus (Branchiostoma beicheri) is the closestliving invertebrate relative of the vertebrates. Morphologically anddevelopmentally it closely resembles the last common ancestor of all vertebrates.In order to get more information from amphioxus genome, a bacterial artificialchromosome (BAC) of Branchiostoma bechli DNA was isolated. Then, ashotgun library was constructed. After verified the insertion percentage andcontains, the library was used for large scale sequencing. Total of 1984 readswas sequenced, including 1885 subclone reads and 99 finish reads. Anaverage 8.15 fold reads assemblied 118Kb length of BAC sequence(unpublished) with 99.54% accurate was gotten after finish.We analyzed the composition of sequence finished. There is 29.91% adenine,20.56% cytosine, 29.32% thymine and 20.20% guanine, the purine is overall50.11%, and G+C content is 40.76%. The total repeat sequence percentage is1.35% and no short interspersed nuclear element was found. One 631bppalindromic sequence fragment was identified. We could not found high levelhomologue sequence at none redundancy nucleotide database. While many shortfragment could be identified at Branchiostoma floridea assembly. Eighteengenes may be enveloped in this BAC. These genes contained average of 6.94extrons and 5.94 introns.A total of 118Kb genome data has been gotten from this BAC, whichrepresents 0.02% of the whole genome size. We could find out new featuresfrom the data. The work has touched the prelude of sequence of branchiostomabeicheri.