Chromosome evolution in Cardamine hybrids and polyploids

Hybrid speciation on the same ploidal level (homoploid hybridization) or via hybridization and genome doubling (allopolyploidy) are relatively common evolutionary processes in land plants. It is estimated that 15% of angiosperm speciation events have resulted from recent polyploid and the legacy of ancient polyploidy (whole-genome duplication) is retained in all angiosperm genomes so far analyzed. The aim of the project is to study chromosome evolution in the Cardamine genus known to contain both recently formed and ancient hybrids and allopolyploids. The low coverage genome skimming data correspond to genome coverages ranging 2-24x.

同倍性水平下的杂交物种形成（homoploid hybridization，同倍性杂交），或是经由杂交与基因组加倍形成的异源多倍化（allopolyploidy），均为陆生植物中较为常见的演化过程。据估算，15%的被子植物（angiosperm）物种形成事件源于近期多倍化事件，且迄今已分析的所有被子植物基因组中均保留了古多倍化（全基因组复制，whole-genome duplication）的演化痕迹。本项目旨在研究碎米荠属（Cardamine）的染色体演化，该属已知兼具近期形成与古老的杂交类群及异源多倍体。本次所用的低覆盖度基因组浅层测序（genome skimming）数据，其基因组覆盖度范围为2~24倍。