Horizontally transferred genes in the genome of Pacific white shrimp, Litopenaeus vannamei.

Background: In recent years, as the development of next-generation sequencing technology, a growing number of genes have been reported as being horizontally transferred from prokaryotes to eukaryotes, most of them involving arthropods. As a member of the phylum Arthropoda, the Pacific white shrimp Litopenaeus vannamei has to adapt to the complex water environments with various symbiotic or parasitic microorganisms, which provide a platform for horizontal gene transfer (HGT).

Results: In this study, we analyzed the genome-wide HGT events in L.

Codon usages of genes on chromosome, and surprisingly, genes in plasmid are primarily affected by strand-specific mutational biases in Lawsonia intracellularis.

In this study, the factors driving genome-wide patterns of codon usages in Lawsonia intracellularis genome are determined. For genes on the chromosome of the bacterium, it is found that the most important source of variation results from strand-specific mutational biases. A lesser trend of variation is attributable to genes that are presumed as horizontally transferred.