Testing relative evolutionary rates and estimating divergence times among six genera of Rhizophoraceae using cpDNA and nrDNA sequences

The molecular phylogenetic trees of 10 species representing 6 genera of the family Rhizophoraceae have been constructed using the sequences of chlorop last genes matK and rbcl as well as the ITS regions of nuclear ribosomal DN A. Relative-rate tests between lineages in these phylogenetic trees have be en performed. On the basis of the results of the relative-rate tests and re lated molecular evolutionary rate data, the divergence times between the li neages are estimated as follows: ( i) the first divergence time in these ge nera is 132.25 million years ago (mya); (ii) the average divergence time be tween two tribes, i.e. inland Legnotideae (except Carallia brachiata) and m angrove Rhizophoreae, is 64.13 mya; and (iii) the average divergence time b etween two inland species, C. garciniaefolia and C. pectinifolia, is 19.92 mya.