Sato Hirotoshi, Murakami Noriaki
Lab of Plant Taxonomy and Evolution, Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Mol Phylogenet Evol. 2008 Jul;48(1):326-34. doi: 10.1016/j.ympev.2008.01.033. Epub 2008 Feb 7.
Among the higher fungi, reproductively isolated cryptic species exist that are morphologically difficult to distinguish owing to a lack of taxonomically useful morphological characters. Mating tests are helpful for detecting reproductive isolation between cryptic species, but are often difficult to perform for higher fungi, especially ectomycorrhizal fungi. In order to identify cryptic species of the ectomycorrhizal genus Strobilomyces more efficiently, lineages were defined based on the nucleotide sequence of two mitochondrial genes. Then the gene flow among lineages was measured using cleaved amplified polymorphic sequences (CAPS) markers designed for single copy nuclear genes. No heterozygosity was observed between different lineages, but within the same lineage heterozygosity was present at the ratio expected given Hardy Weinberg equilibrium. These results show that the mtDNA lineages are separate Mendelian populations, possibly cryptic species that are reproductively isolated from each other.
在高等真菌中，存在一些生殖隔离的隐性物种，由于缺乏具有分类学价值的形态特征，在形态上很难区分。交配试验有助于检测隐性物种之间的生殖隔离，但对于高等真菌，尤其是外生菌根真菌，往往难以进行。为了更有效地鉴定外生菌根属真菌拟小牛肝菌的隐性物种，基于两个线粒体基因的核苷酸序列定义了谱系。然后，使用为单拷贝核基因设计的酶切扩增多态性序列（CAPS）标记来测量谱系间的基因流。在不同谱系之间未观察到杂合性，但在同一谱系内，杂合性以符合哈迪-温伯格平衡预期的比例存在。这些结果表明，线粒体DNA谱系是独立的孟德尔种群，可能是彼此生殖隔离的隐性物种。
