Another recent study [ 24] showed that duplications of Group I Nme genes occurred independently more than once in invertebrates, besides well described duplications and diversifications of Group I Nme to Nme1, 2, 3 and 4 in vertebrate lineage, and that duplication in N. vectensis is also an independent event unrelated to the origin of Nme1 and Nme2.
At the base of the trees, relationships among the salivarius, downei, mutans, pyogenic, and bovis groups were poorly resolved, possibly reflecting the effect of frequent LGT during the early diversification of these groups.
The idea that coevolution between angiosperms and insects led to diversification of both groups has long been popular.
It is widely accepted that angiosperm flowers and their insect pollinators have influenced each other's evolution, but there is still considerable uncertainty about whether or not coevolution has been a major process in the diversification of these groups.
To quantify vicariance events in the early diversification of both groups, we estimated ancestral distributions for ingroup nodes using dispersal-vicariance analyses performed by the program DIVA 1.1 [39].
There is support for this in the increased diversification of insect groups that have passed through such an oscillation in diet breadth as compared to their primitively specialised sister-groups [5], [11].
This report examines the question of whether duplications and homeotic changes have played a role in new body configuration change in three events of special biological interest-the emergence of mammals among the synapsid amniotes, the diversification of mammal groups in the Late Cretaceous, and the emergence of "hominiforms" among the catarrhine primates in the Early Miocene.
Losses occurred later, during the diversification of these groups, as exemplified in rodents.
Adaptive radiations are believed to be responsible for the diversification of many groups of organisms [ 1, 2].
Insect pollinators of Tricyrtis may also have played important roles in co-evolution, leading to the diversification of the groups.
Positive selection is also involved in the diversification of several groups of plant developmental transcription factors [ 12- 17].
