Genetic Relationship And Diversity Of Mallotus In Hunan

This research is about the relationship and genetic distance of 12 Mallotus species in Hunan (M. tenuifolius, M. Barbatus, M. Japonicus, M. millietii, M. Microcarpus, M. Apelta, M. repandus var. chrysocarpus, M. lianus, M. taoyuanensis, M. Dunnii, M. philippensis, M. paxii) as well as Discocleidion rufescens and Alchornea hunanensis, combining ISSR and classical Taxonomy.Method CTAB2 is found to be effective in genomic DNA extraction. The optimized reaction condition of ISSR-PCR for Mallotus species in Hunan was: 10ngDNA, 0.5UTaq DNA polymerase(TAKARA), 0.2μmol/L primer, 0.2mmol/L dNTPs, 1.5mmol/L MgCl₂ in a total volume of 10 μl . The amplification condition was 1.5 min at 94℃, 35×45s at 94℃, 45s at 52℃-55℃, 1.5min at 72℃, 7min at 72℃. We analyzed ISSR-PCR results, using POPGENE software. The results show: 1) The genetic diversity of Mallotus is in high level, in accordance with its far-ranging geographic distribution. 2) There is an apparent difference between Mallotus species and Discocleidion rufescens, as well as Mallotus species and Alchornea hunanensis. 3) It is reasonable to cluster M. millietii, M. repandus var. chrysocarpus and M. philippensis. 4) M. tenuifolius and M. Japonicus are two different species. 5) The latest found M. taoyuanensis is a new species of mallotus. It is not a hybridized species of M. paxii population, but has a closest relationship with M. microcarpus. Still, it needs further research to testify whether M. taoyuanensis belongs to a new section of mallotus.