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Multiple autopolyploidizations and range expansion of Allium przewalskianum Regel. (Alliaceae) in the Qinghai‐Tibetan Plateau
Author(s) -
WU LILI,
CUI XIEKUI,
MILNE RICHARD I.,
SUN YONGSHUAI,
LIU JIANQUAN
Publication year - 2010
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2010.04613.x
Subject(s) - biology , ploidy , plateau (mathematics) , chloroplast dna , range (aeronautics) , haplotype , glacial period , phylogeography , ecology , botany , evolutionary biology , genome , phylogenetics , paleontology , genetics , allele , gene , mathematical analysis , materials science , mathematics , composite material
We used the Allium przewalskianum diploid–tetraploid complex on the Qinghai‐Tibetan Plateau (QTP) as a model to examine how this complex responded to the Quaternary climatic oscillations, and whether multiple autopolyploidizations have occurred. We sequenced five chloroplast DNA (cpDNA) fragments ( acc D‐ psa I, trn H‐ psb A, trn L‐ trn F, trn S‐ trn G and rpl 16‐intron) in 306 individuals (all of known ploidy level) from 48 populations across the distribution of this species complex. We identified a total of 32 haplotypes—11 in diploids only, 13 in tetraploids only, and 8 found in both cytotypes. This, plus network analyses, indicated that tetraploids have arisen independently from diploids at least eight times. Most populations in the eastern QTP contained multiple haplotypes, but only a single haplotype was found for 17 tetraploid populations on the western QTP, suggesting a recent colonization of the western QTP. We further found that this species complex underwent an earlier range expansion around 5–150 thousand years ago (kya), after the largest glacial period (800–170 kya) in the QTP. In addition, the high frequencies of tetraploids in the QTP suggested that the tetraploid A. przewalskianum cytotype has evolutionary advantages over diploids in colonizing and/or surviving the arid habitats of the QTP.