Comparing chromosomal and mitochondrial phylogenies of the Indriidae (Primates, Lemuriformes).

The Malagasy primate family Indriidae comprises three genera with up to 19 species. Cytogenetic and molecular phylogenies of the Indriidae have been performed with special attention to the genus Propithecus. Comparative R-banding and FISH with human paints were applied to karyotypes of representatives of all three genera and confirmed most of the earlier R-banding results. However, additional chromosomal rearrangements were detected. A reticulated and a cladistic phylogeny, the latter including hemiplasies, have been performed. Cladistic analysis of cytogenetic data resulted in a phylogenetic tree revealing (1) monophyly of the family Indriidae, (2) monophyly of the genus Avahi, (3) sister-group relationships between Propithecus diadema and Propithecus edwardsi, and (4) the grouping of the latter with Indri indri, Propithecus verreauxi, and Propithecus tattersalli, and thus suggesting paraphyly of the genus Propithecus. A molecular phylogeny based on complete mitochondrial cytochrome b sequences of 16 species indicated some identical relationships, such as the monophyly of Avahi and the sister-group relationships of the eastern (P. diadema and P. edwardsi) to the western Propithecus species (P. verreauxi, Propithecus coquereli, and P. tattersalli). However, the main difference between the molecular and cytogenetic phylogenies consists in an early divergence of Indri in the molecular phylogeny while in the chromosomal phylogeny it is nested within Propithecus. The similarities and differences between molecular and cytogenetic phylogenies in relation to data on the species' geographic distributions and mating systems allow us to propose a scenario of the evolution of Indriidae. Chromosomal and molecular processes alone or in combination created a reproductive barrier that was then followed by further speciation processes.

Comparing chromosomal and mitochondrial phylogenies of sportive lemurs (Genus Lepilemur, Primates).

In recent years several new sportive lemur species (genus Lepilemur) have been described. In contrast to other lemur taxa, the genus shows comparatively high chromosomal variability, which, in addition to molecular data, can be used to infer phylogenetic relationships within the genus. By comparing R-banding patterns and fluorescence in-situ hybridization data, we detected chromosomal rearrangements that occurred during speciation within the genus. The analysis of these data with cladistic methods resulted in a dichotomic phylogenetic tree comparable to that obtained from mitochondrial sequence data. However, a phase of reticulation can not be excluded from the evolution of Lepilemur. Although some incongruences were detected, both phylogenies show similar patterns concerning relationships of the basal and terminal splits. We therefore hypothesize that both, chromosome rearrangements and molecular mutations, alone or in combination, contributed to the speciation process in sportive lemurs.

Phylogenetic history of the Sifakas ( Propithecus: Lemuriformes) derived from cytogenetic studies.

The R-banded karyotypes of the different subspecies of Propithecus diadema and P. verreauxi are compared to each other and to that of P. tattersalli, as well as those previously reported of Indri indri and Avahi laniger. This comparison shows that the different subspecies of P. verreauxi possess the same karyotype and that, among P. diadema, P. d. diadema and P. d. perrieri share the same karyotype differing from that of P. d. edwardsi by one Robertsonian translocation. The karyotype of P. tattersalli differs at least through 17 and 9 rearrangements from those of P. diadema and P. verreauxi, respectively. This provides strong arguments in favor of its specific status. The phylogenetic diagram proposed confirms the early separation of Avahi and the relatively late divergence of the four other species. A populational evolution has occurred between these four species, P. tattersalli and P. verreauxi sharing the largest number of rearrangements (six), while the numbers of rearrangements shared by the other species are two for Indri and P. verreauxi, three for P. tattersalli and Indri, and three for P. tattersalli and P. diadema. No branch is common to two species of Propithecus.

Chromosomal evolution of the Hapalemur griseus subspecies (Malagasy Prosimian), including a new chromosomal polymorphic cytotype.

A cytogenetic study has been performed on Hapalemur griseus caught in different locations of the eastern and northern forests of Madagascar. This allowed the determination of the more precise distribution areas of the different subspecies and the isolation of a new cytogenetic polymorphic subspecies of H. griseus. The chromosomal changes distinguishing the different subspecies are Robertsonian translocations and gain of heterochromatin. The phylogeny established on chromosome comparison is compatible with the geographic distribution of the subspecies.