Polyploidy in gymnosperms - Insights into the genomic and evolutionary consequences of polyploidy in Ephedra
Polyploidy in gymnosperms - Insights into the genomic and evolutionary consequences of polyploidy in Ephedra
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DOI：
10.1016/j.ympev.2020.106786
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发表时间：
2020-06-01
影响因子：
4.1
通讯作者：
Leitch, Ilia J.
中科院分区：
文献类型：
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作者：
Ickert-Bond, Stefanie M.;Sousa, Aretuza;Leitch, Ilia J.
虽然多倍化被认为是蕨类植物和被子植物的主要进化驱动力，但人们对其在裸子植物中的影响知之甚少，裸子植物的多倍化频率要低得多。我们探讨麻黄属，以评估（一）基因组大小的多样性的程度，在属和多倍体的核DNA含量的演变的影响，和（ii）确定在基因组大小和多倍体的变化发生在时间和空间。利用系统发育框架，结合87%和67%的麻黄属植物的染色体组大小和核型，探讨了麻黄属植物的倍性演化及其全球分布格局。多倍体被证明是非常普遍的，有41个物种（83%）是多倍体（高达8倍）或具有多倍体细胞型-最高的频率和水平报告的任何裸子植物。基因组大小也是多样的，其值范围接近5倍（8.09-38.34 pg/1C）-任何裸子植物家族的最大范围-并且与倍性水平成比例增加（即没有基因组缩小）。我们的研究结果提供了新的数据，支持裸子植物有一个更保守的基因组进化模式相比，被子植物的观点。
While polyploidization is recognized as a major evolutionary driver for ferns and angiosperms, little is known about its impact in gymnosperms, where polyploidy is much less frequent. We explore Ephedra to evaluate (i) the extent of genome size diversity in the genus and the influence polyploidy has had on the evolution of nuclear DNA contents, and (ii) identify where shifts in genome size and polyploidy have occurred both temporally and spatially. A phylogenetic framework of all Ephedra species together with genome sizes and karyotypes for 87% and 67% of them respectively, were used to explore ploidy evolution and its global distribution patterns. Polyploidy was shown to be extremely common, with 41 species (83%) being polyploid (up to 8 x) or having polyploid cytotypes - the highest frequency and level reported for any gymnosperm. Genome size was also diverse, with values ranging similar to 5-fold (8.09-38.34 pg/1C) - the largest range for any gymnosperm family - and increasing in proportion to ploidy level (i.e. no genome downsizing). Our findings provide novel data which support the view that gymnosperms have a more conserved mode of genomic evolution compared with angiosperms.