Chromosomal evolution in Malagasy lemurs: X. chromosomal banding studies of Propithecus diadema edwardsi and Indri indri and phylogenic relationships between all the species of the Indriidae

The R-banded karyotypes of two Indriidae, Propithecus diadema and Indri indri, are described and compared with each other and with those of the other species of this family, previously reported, Avahi laniger and Propithecus verreauxi. These comparisons show that 30 chromosomal rearrangements, including 21 Robertsonian translocations and eight pericentric inversions, differentiate these karyotypes. A phylogenic diagram is proposed, showing the early separation of Avahi and the relatively late divergence of the three other species. A populational evolution has occurred between the three other species, but Indri is clearly separated from the two other species by at least five complex rearrangements, although it shares four Robertsonian translocations with P. verreauxi but not P. diadema.     

Notes on the distribution ofLepilemur septentrionalis andL. mustelinus in Northern Madagascar

The superfamily Lemuridae, which includes some of the most primitive extant primates, is confined to the island of Madagascar. The speciesL. septentrionalis lives in the north of Madagascar. The geographical distribution of each of the four recognized subspecies is fairly well defined except for the southern limits of the southernmost subspecies, namelyL. s. andrafiamenensis. Similarly the southern and northern limits of distribution ofL. mustelinus are uncertain. Two expeditions were carried out, one in the south of the Andrafiamena mountain chain, the other in the north of the eastern forest, south of Vohemar to gain new information concerning the present southern limits ofL. septentrionalis and northern limit ofL. mustelinus. L. s. andrafiamenensis was found to the left of the Ambilobe-Vohemar road from Betsiaka to Maromokotra and on the left bank of the river Loky, to the coast.L. mustelinus was found only on the right bank of the river Lokoho to the coast. Both survey indicate smaller ranges than those indicated in recent publications, probably a result of continued human encroachment.     

Phylogenetic relation between Lepilemuridae and other lemuriform families

A comparative study between the ancestral karyotype of the Lepilemuridae and that of the other lemuriforms showed that there are strong arguments supporting the hypothesis that the lepilemurs derive directly from the latter, essentially through end-to-end translocations. These results support a monophyletic origin of the lemurs of Madagascar and the classification of the Lepilemuridae as a separate family.     

Interspecific nucleotide sequence differences in the cytochrome B gene of indriidae (Primates, Strepsirhini)

The comparison of partial sequence of the mitochondrial cytochrome b gene nucleotides for different Indriidae allowed us to confirm the species status ofAvahi laniger, A. occidentalis, and Propithecus tattersalli. The nucleotide sequence allowed also to propose a phylogenetic tree which is discussed taking into account morphological, cytogenetic and former molecular biology data.     

Cytogenetic study of the endemic Malagasy lemurs subfamily Cheirogaleinae Gregory 1915

Karyotypes were determined on 27 lemurs from six species of what has been called the “subfamily” of Cheirogaleinae : Microcebus murinus murinus (2), M. murinus rufus (2), M. coquereli (5), Phaner furcifer (6), Cheirogaleus medius (9), and C. major (3). The cytogenetic study of these animals reveals that this “subfamily” contains in fact two groups, (a) — Microcebus and Cheirogaleus, and (b) — Phaner. The karyotype of the first two genera has a fundamental number (FN) equal to 66 and the karyotype of the third genus has an FN equal to 62. This result and the fact that Phaner has a particular scent-marking gland, knuckle pads, and finger prints markedly different from those of other genera agree with the view that this animal belongs to a special subfamily, Phanerinae, while the two other genera constitute the subfamily of Cheirogaleinae. These two subfamilies constitute the family of Cheirogaleidae.     

Chromosomal evolution in Malagasy lemurs. IX. Chromosomal banding studies of Lepilemur mustelinus, L. dorsalis, and L. edwardsi

The karyotypes of three Lepilemuridae species, Lepilemur mustelinus, L. edwardsi, and L. dorsalis, are described and compared to those of three Lepilemur species previously reported. The phylogenetic relationships between the six species and their presumed last common ancestor are given. The results obtained, and the comparison with other groups, strongly suggest a monophyletic origin for all Malagasy lemurs.     

Synapsis and synaptic adjustment in an infertile human male heterozygous for a pericentric inversion in chromosome 1

Summary Synapsis and synaptic adjustment were analyzed, using electron microscopy in silver stained surface microspreads of inversion-bearing spermatocytes, in an infertile human male with an inherited pericentric inversion in chromosome 1. Possible reasons for his infertility are discussed.     

Aberrations of the synaptonemal complexes in a male 46,XY,-14,+der(14)t(Y;14)

An unbalanced translocation 46,XY,-14,+der(14)t(Y;14)(q11;p11) was observed in an azoospermic male, with reduced spermatogenesis and absent spermiogenesis. At the pachytene stage of spermatocyte 1, the segments of the 2 Y chromosomes, fluorescent with quinacrine mustard, were always found close together. This proximity was also demonstrated by the study of synaptonemal complexes, which showed, in addition, an unusual hypercondensation of the proximal segment of bivalent 14, adjacent to the translocated Y chromosome. This allows us to propose that this hypercondensation might correspond to an inactivation of the translocated autosome, which could be responsible of the degeneration of the germ cells.     

Supernumerary chromosomes and spermatogenesis in a human male carrier

Screening for lactate dehydrogenase (LDH) subunit deficiencies was performed on 2880 blood samples from healthy individuals in the Fukuoka Prefecture in Japan by means of electrophoresis. The frequencies of heterozygotes with either LDH-A or LDH-B deficiency were found to be 0.104% at each locus. These estimated frequencies of either LDH-A or LDH-B deficiencies were slightly lower than, but not significantly different from, those found previously in Shizuoka Prefecture. The genetic mutations in individuals heterozygous for LDH-B deficiency were analyzed by the polymerase chain reaction and DNA conformation polymorphism. Abnormal migration patterns were observed in individuals heterozygous for LDH-B deficiency. Subsequent sequence determination of the mutant alleles revealed three novel mutations: an eight-base duplication in exon 3, a four-base duplication in exon 4, and a one-base deletion in exon 7 of the LDH-B gene. These three mutations result in frameshift translation and premature termination. In addition, the mutations resulting in the duplication of eight or four nucleotides appear to cause a decrease in the levels of LDH-B mRNA.