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.

Fluorescence in situ hybridization sperm analysis of six translocation carriers provides evidence of an interchromosomal effect.

OBJECTIVE: To investigate the existence of an interchromosomal effect in balanced reciprocal translocation carriers and to evaluate their risk of having an affected child or repeated spontaneous abortions. DESIGN: Analysis of chromosomal sperm content by fluorescence in situ hybridization (FISH) using probes for chromosomes 1, 15, 16, 17, 18, X, and Y. SETTING: University hospital. PATIENT(S): Six male carriers of balanced chromosome rearrangements, one with normal sperm parameters and five with oligoasthenoteratozoospermia, and seven fertile controls. INTERVENTION(S): Fluorescence in situ hybridization for chromosomal enumeration on sperm samples. MAIN OUTCOME MEASURE(S): Rate of disomy for the studied chromosomes. RESULT(S): A total of 123,842 spermatozoa were scored (82,181 for controls and 41,661 for patients). For each patient, at least one chromosome studied presented a significantly increased rate of disomy. One patient showed a clear interchromosomal effect for at least three of the six chromosomes studied. Disomy rates were statistically significantly and inversely correlated with the total progressive motility of spermatozoa. CONCLUSION(S): The observed interchromosomal effect seems to be translocation, patient, and chromosome dependent. Variable effects were observed, according to the chromosome studied. When we looked at patients carrying the same translocation, the level of disomy rate was variable and affected different chromosomes.

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.