2016年07月12日
熱帯医学研究所カレトンリチャード准教授、ジュンカオ博士(中国)、アナブペイン博士(サウジアラビア)らの共同研究グループは、四日熱マラリア原虫と卵形マラリア原虫の全ゲノムシーケンス解析を行ない、それらの全ゲノム情報を解読しました。
この2つのマラリア種は熱帯地域の深刻な病であるにも関わらず、十分な量のDNAを確保するのが難しいために今までその遺伝情報が分かっていませんでした。今回の全ゲノム情報の発表は、今後新しい治療薬とワクチン開発に繋がるものと思われます。
成果は、国際科学雑誌『International Journal for Parasitology電子版』(2016年7月5日)に発表しました。
Genome-scale comparison of expanded gene families in Plasmodium ovale wallikeri and Plasmodium ovale curtisi with Plasmodium malariae and with other Plasmodium species
Abstract
Malaria in humans is caused by six species of Plasmodium parasites, of which the nuclear genome sequences for the two Plasmodium ovale spp., P. ovale curtisi and P. ovale wallikeri, and Plasmodium malariae have not yet been analyzed. Here we present an analysis of the nuclear genome sequences of these three parasites, and describe gene family expansions therein. Plasmodium ovale curtisi and P. ovale wallikeri are genetically distinct but morphologically indistinguishable and have sympatric ranges through the tropics of Africa, Asia and Oceania. Both P. ovale spp. show expansion of the surfin variant gene family, and an amplification of the Plasmodium interspersed repeat (pir) superfamily which results in an approximately 30% increase in genome size. For comparison, we have also analyzed the draft nuclear genome of P. malariae, a malaria parasite causing mild malaria symptoms with a quartan life cycle, long-term chronic infections, and wide geographic distribution. Plasmodium malariae shows only a moderate level of expansion of pir genes, and unique expansions of a highly diverged transmembrane protein family with over 550 members and the gamete P25/27 gene family. The observed diversity in the P. ovale wallikeri and P. ovale curtisi surface antigens, combined with their phylogenetic separation, supports consideration that the two parasites be given species status.
http://www.sciencedirect.com/science/article/pii/S0020751916301357