Please use this identifier to cite or link to this item: http://rportal.lib.ntnu.edu.tw:80/handle/20.500.12235/103832
Title: 外來龜種對金門地區原生金龜的遺傳入侵
Genetic introgression from invasive Mauremy species to native M. reevesii in Kinmen
Authors: 林思民
Lin, Si-Min
李昱
Lee, Yu
Keywords: 金龜
金門
停戰區
遺傳入侵
野生動物貿易
Mauremys reevesii
Kinmen
demilitarized zone
genetic introgression
wildlife trade
Issue Date: 2015
Abstract: 金門是金龜(Mauremys reevesii)在台灣唯一擁有穩定族群的棲地,金龜也是島上除了中華鱉之外最優勢的原生龜種。然而隨著寵物貿易的流通,也可能對當地的龜鱉類群聚產生相當程度的改變。我們在金門島上2011至2013年進行金門的淡水龜普查中,不僅發現了過去在當地較為罕見的斑龜(M. sinensis),還觀察到疑似金龜與斑龜、金龜與柴棺龜雜交的個體。這些疑似雜交的表形顯示在生殖隔離不完全的情形下,不同種的淡水龜可能發生雜交的現象。若雜交的後代仍具有生殖能力,這些近緣龜種可能會對金龜產生遺傳入侵(genetic introgression)的負面效應。為了瞭解斑龜與柴棺龜是否會與原生的金龜雜交,並評估遺傳滲入的嚴重程度,找出影響池塘雜交程度的因子,我們採用淡水龜的表形、粒線體cytochrome b基因序列、與13組微衛星基因座進行遺傳滲入的檢測,並用池塘的環境資料:距主要道路距離(DM)、距次要道路距離(DS)、植被覆蓋程度(VL)、池塘水面上植物量(VW)、池塘邊緣形式(PS)、池塘面積大小(PA)、池塘深度(PD)以及池塘內斑龜的數量等因子,利用廣義線性迴歸分析(general linear regression)檢視上述各項棲地因子是否對金龜的雜交程度造成影響。結果顯示金門的金龜確實會與斑龜和柴棺龜雜交。從粒線體基因與表形的比較結果來看,表形與基因型不一致的金龜共有10隻,其中有6隻金龜帶有斑龜的基因型;有4隻帶有柴棺龜的基因型。利用微衛星基因座,並使用STRUCTURE分群判別,在全部使用純系龜隻的情況下,三種淡水龜可以清晰的分群,最佳分群數為三。但是當加入金門當地的金龜之後,最佳分群數為二。表形初步判定為雜交的19隻淡水龜,有18隻確認為斑龜或柴棺龜和金龜的雜交龜。而表形看似金龜的241隻個體當中,有28隻遭到斑龜或柴棺龜的遺傳入侵。總和來說,原生金龜有高達11.6%的比例與近緣龜種雜交。採樣的44個樣點裡有22個樣點採集到金龜,而其中有16個水域(72.7%)有雜交的現象產生。影響池塘雜交的程度則與共域的外來斑龜數量與池塘的人工化程度有關,斑龜的數量與池塘雜交的程度呈現顯著的正相關(P=0.0002),天然的池塘受到遺傳入侵的程度也顯著地低於人工池塘(P=0.037)。研究顯示這三種已經分化的淡水龜若受到人類行為的干擾(例如異種共同圈養,或是人為進行的釋放),很可能會提升種間雜交的機會,對物種的保育有不利的影響。
Kinmen Archipelago, comprising Greater and Lesser Kinmen islands, is located on the coastline of China and sustaining a stable population of Chinese pond turtle (Mauremys reevesii). Since this turtle is widely consumed for food and medical purposes, Kinmen has become one of the most important natural habitats for the conservation of this species in Taiwan. However, community of turtles in Kinmen Islands might have changed in recent years because of human activities. Chinese stripe-necked turtle (M.sinensis), which was extremely rare in literature, was found on the islands; while genetic introgression was suspected from M. sinensis and the even rarer Asian brown pond turtle (M. mutica). In this study, we aim to evaluate the level and magnitude of genetic introgression among closely related turtles by using mitochondrial cytochrome b sequences and 13 microsatellite loci. We further used 8 environmental and biological factors of the ponds to conduct general linear regression in order to figure out the critical factors which influence the hybrid rates of the turtles. Our results indicated strong evidences for the hybridization between M. reevesii and M. sinensis, and occasionally between M. reevesii and M. mutica. Six turtles showed inconsistence between their M. reevesii morphology but M. sinensis mitochondrial haplotypes; while 4 others showed M.reevesii morphology but M. multica haplotypes. Microsatellite genotyping further revealed 18 among 19 turtles with intermediate form and 28 among 241 M.reevesii individuals confirmed as hybrids between M.reevesii and M. sinensis or M . mutica. Among the 44 water bodies we sampled, 22 localities have M. reevesii records and 16 (72.7%) have hybrids detected. The degree of introgression in a pond is positively correlated to the abundance of M. sinensis (P = 0.0223) and the artificial modification of the pond (P = 0.0002). Our research shows that human mediated dispersal of Mauremys and destruction of natural habitats may increase the possibility of interspecies hybridization, and cause negative impact to the endangered species.
URI: http://etds.lib.ntnu.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=%22http://etds.lib.ntnu.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=id=%22G060043021S%22.&%22.id.&
http://rportal.lib.ntnu.edu.tw:80/handle/20.500.12235/103832
Other Identifiers: G060043021S
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