兩棲類擴散能力有限,，容易受歷史地質(zhì)、氣候事件等因素的影響而產(chǎn)生分歧演化，是研究生物地理的良好模式生物。
楊君興研究員課題組（張明旺,，饒定齊，楊君興,，余國華等）通過對分布于云南哀牢山和無量山的哀牢髭蟾的種群分子譜系地理學(xué)研究發(fā)現(xiàn)：該種群分為四個遺傳差異明顯的譜系,，分化時間與晚中新世至中上新世哀牢山的快速抬升和同時并行的紅河的快速下切形成高山峽谷的古地質(zhì)時間吻合。由于該種只分布中海拔（2000米左右）,，即接近山頂?shù)某＞G闊葉林下濕冷的溪流生境中,，因此低海拔干熱的河谷成為其不適宜的生境而成為種群間基因交流的障礙（陸上的島嶼效應(yīng)）。同時,，受更新世冰期的影響,，在該種的南部的分布區(qū)有不同譜系的重疊區(qū)（從北向南遷移）。該研究結(jié)果已于2010年發(fā)表在Molecular Phylogenetics and Evolution (54: 47–58)上,。（生物谷Bioon.com）
生物谷推薦原文出處：
Mol Phylogenet Evol. 2010 Jan;54(1):47-58. Epub 2009 Oct 19.
Molecular phylogeography and population structure of a mid-elevation montane frog Leptobrachium ailaonicum in a fragmented habitat of southwest China.
Zhang M, Rao D, Yang J, Yu G, Wilkinson JA.
Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
Abstract
Leptobrachium ailaonicum is a vulnerable anuran restricted to a patchy distribution associated with small mountain streams surrounded by forested slopes at mid-elevations (approximately 2000-2600m) in the subtropical Mount Wuliang and Mount Ailao ranges in southwest China (Yunnan Province) and northern Vietnam. Given high habitat specificity and lack of suitable habitat in lower elevations between these ranges, we hypothesized limited gene flow between populations throughout its range. We used two mitochondrial genes to construct a phylogeographic pattern within this species in order to test our hypothesis. We also examined whether this phylogeographic pattern is a response to past geological events and/or climatic oscillations. A total of 1989 base pairs were obtained from 81 individuals of nine populations yielding 51 unique haplotypes. Both Bayesian and maximum parsimony phylogenetic analyses revealed four deeply divergent and reciprocally monophyletic mtDNA lineages that approximately correspond to four geographical regions separated by deep river valleys. These results suggest a long history of allopatric separation by vicariance. The distinct geographic distributions of four major clades and the estimated divergence time suggest spatial and temporal separations that coincide with climatic and paleogeographic changes following the orogeny and uplift of Mount Ailao during the late Miocene to mid Pliocene in southwest China. At the southern distribution, the presence of two sympatric yet differentiated clades in two areas are interpreted as a result of secondary contact between previously allopatric populations during cooler Pleistocene glacial cycles. Analysis of molecular variance indicates that most of the observed genetic variation occurs among the four regions implying long-term interruption of maternal gene flow, suggesting that L. ailaonicum may represent more than one distinct species and should at least be separated into four management units corresponding to these four geographic lineages for conservation.
