運用分子標記鑑別野生草蝦之遺傳品系與保育單元

Abstract

D-loop區（粒線DNA）和微隨體可應用於個體鑑識、測試海洋生物地理假說，以及確認需保育族群等各方面。草蝦(Penaeus monodon)是應用此類分析之理想對象，因其分佈廣泛、橫跨於「赫胥黎線」(生物地理線)兩側；此外為確保養殖種蝦之來源與品質，亦需持續對野生族群進行監測。 本研究利用D-loop區序列以及6個微隨體基因座，對菲律賓的Leyte、Surigao 、印尼的Pangandaran等三個野生草蝦族群，各30隻個體進行族群遺傳分析。使用6個微隨體基因座進行個體鑑識分析，其鑑別率在印尼的Pangandaran族群和菲律賓的Surigao族群可達100%；在菲律賓的Leyte族群則為92.31%。在鑑別演化單位方面，由親緣關係分析可知，並無任何單一族群可視為「演化顯著單位」；惟結合菲律賓的二個族群可視為一個「管理單位」。而影響此三族群分佈的主要因素，除「赫胥黎線」外，更新世時的海平面變化以及現今的海洋環流亦有影響。

D-loop (mitochondrial/mtDNA) and microsatellites (nuclear) could assign individuals to populations for aquaculture, test marine biogeographical hypotheses on the distribution of organisms and identify populations to be prioritized for conservation. The black tiger shrimp, Penaeus monodon, is ideal for d-loop and microsatellite analyses because it is widely distributed throughout a biogeographic line called Huxley’s Line and monitoring of wild populations is necessary to maintain the quality of the shrimp seed sources. This study amplified d-loop sequences and tested six microsatellites on wild populations of black tiger shrimp from Leyte; Surigao del Norte and Pangandaran, West Java. Thirty individuals were collected from each population. The proportions of properly assigned samples using microsatellites were 100% in Pangandaran and Surigao and 92.31% in Leyte. No population was considered as an evolutionary significant unit because there was no reciprocal monophyly based on the resulting phylogenetic tree. Only Leyte combined with Surigao can be considered as management unit because it passed a test on significant divergence of allele frequencies at nuclear loci. Pleistocene sea levels and present-day ocean circulation rather than the Huxley’s line alone affect the distribution of the three populations