HYBRIDIZATION IS ASSOCIATED WITH CHANGES IN SEXUAL SYSTEM IN THE BRYOPHYTE GENUS ATRICHUM
HYBRIDIZATION IS ASSOCIATED WITH CHANGES IN SEXUAL SYSTEM IN THE BRYOPHYTE GENUS ATRICHUM
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DOI：
10.3732/ajb.1400494
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发表时间：
2015-04-01
影响因子：
3
通讯作者：
Jesson, Linley K.
中科院分区：
文献类型：
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作者：
Perley, Danielle S.;Jesson, Linley K.
研究结论：超过50%的蝙蝠有单独的性别，并且在两性结合和单独的性别之间发生了许多转变。多倍体和杂交是一个近似的机制，假设导致进化过渡到雌雄同体的brabetes，因为性别是在单倍体阶段和非多倍体雌雄异株物种的男性有一个单一的V染色体和女性的U。如果异源多倍体的配子体同时具有U和V染色体，就可能产生两性畸形。我们研究了多倍体和雌雄同体之间的关联在brendiete属Atrichum，其中有物种的配子体可以是单倍体，二倍体，或三倍体，和一些物种有雌雄同体的个人。我们从三个质体区域的序列中产生了Atrichum的同源性（rbcL，rps 4，和trnL-trnF）和核基因Leafy/Floricaula的第二内含子，以进一步了解单倍体，二倍体，主要结果：在二倍体和三倍体个体中存在多个叶/花茎属序列，但不是单倍体，这与二倍体和三倍体物种的独立异源多倍体起源是一致的。异源多倍性与可能获得的雌雄同体在三倍体的波叶藓和可能的二倍体A。altecristatum，而异源多倍体A. crispulum（二倍体在配子体水平）。结论：这些结果突出了杂交和多倍体在性系统进化中的作用，但二倍体（异源多倍体）雌雄异株物种的存在表明，其他因素可能会影响性系统的维护后，进化过渡。
Premise of the study: Over 50% of bryophytes have separate sexes, and numerous transitions have occurred between combined and separate sexes. Polyploidy and hybridization is one proximate mechanism hypothesized to cause evolutionary transitions to hermaphroditism in bryophytes because sex is expressed at the haploid stage and in nonpolyploid dioecious species males have a single V chromosome and females a U. Hermaphroditism can arise if gametophytes of allopolyploids have both U and V chromosomes. We examined the association between polyploidy and hermaphroditism in the bryophyte genus Atrichum, which has species where gametophytes can be haploid, diploid, or triploid, and some species have hermaphroditic individuals.Methods: We generated phylogenies of Atrichum from sequences of three plastid regions (rbcL, rps4, and trnL-trnF) and the second intron for the nuclear gene Leafy/Floricaula to further understand the relationships among haploid, diploid, and triploid species, and those with combined or separate sexes.Key results: The existence of multiple sequences of Leafy/Floricaula in diploid and triploid, but not haploid, individuals is consistent with independent allopolyploid origins of the diploid and triploid species. Allopolyploidy was associated with a likely gain in hermaphroditism in triploid Atrichum undulatum and possibly diploid A. altecristatum, but not in the allopolyploid A. crispulum (diploid at the gametophyte level).Conclusions: These results highlight a role for hybridization and polyploidy in sexual system evolution, but the presence of diploid (allopolyploid) dioecious species suggest that other factors may influence the maintenance of sexual systems after an evolutionary transition.