Bats of the genus Scotophilus are distributed throughout sub-Saharan Africa, parts of southern and Southeast Asia, a majority of the Indomalayan Islands, Reunion Island, and Madagascar. The genus is composed of 14 recognized species with seven distributed throughout sub-Saharan Africa including: (S. dinganii (A. Smith, 1833), S. leucogaster (Cretzschmar, 1830), S. nigritellus de Winton, 1899, S. nigrita (Schreber, 1774), S. nucella Robbins, 1983, S. nux Thomas, 1904, and S. viridis (Peters, 1852). The remaining species include four from southern and southeast Asia (S. celebensis Sody, 1928; S. collinus Sody 1936; S. heathi (Horsfield, 1831); S. kuhlii Leach, 1821), two on Madagascar (S. sp. nov. Goodman et al., in press; and S. robustus Milne-Edwards, 1881), and one endemic to Reunion Island (S. borbonicus (E. Geoffroy, 1803). The systematics and taxonomy of this genus have been controversial and continue to be confusing. The genus is plagued with problems in species definition and the systematic relationships among members of the genus are poorly understood. The major goal of this study was to use a molecular phylogenetic approach to clarify some of the controversy and confusion surrounding the members of this genus. Nucleotide differences from mtDNA and the Y chromosome were used to examine phylogenetic patterns within Scotophilus. Based on these data two new species of Scotophilus were identified. Phylogenetically, African Scotophilus were found to comprise a monophyletic group with S. nux as the most basal African taxon. Overall, the Asian S. kuhlii was the most basal taxon. A distant relationship was identified between S. kuhlii and S. heathi, the other Asian species examined. The multiple origins of Malagasy Scotophilus are apparent as the two Malagasy taxa in the study do not share a sister-group relationship. The large bodied S. nigrita is closely related to S. dinganii and the S. dinganii-like species all share a close relationship. S. nigrita has a S. dinganii-like mtDNA haplotype and a very distinct zfy haplotype, suggesting a possible hybridization event with a S. dinganii-like ancestor.

Sequence variation was examined for the Zinc-finger Y (zfy) gene and the mitochondrial control region for two species of pinnipeds, the Steller sea lion (Eumetopias jubatus) and harbor seal (Phoca vitulina). The two species differ in aspects of their breeding strategies, dispersal, and life histories. Comparable stock sample sizes of males from each species were taken from localities that span at least one wellrecognized phylogeographic stock as defined by mtDNA markers. Variation in zfy, a strictly paternally inherited marker located on the Y chromosome, was low in both species. An interesting pattern of subdivision was found for zfy in harbor seals that was concordant with population subdivision for mtDNA. In Steller sea lions, no such concordant pattern was evident with only a single rare zfy variant being observed. One explanation for the different patterns observed is that dispersal is less in male harbor seals than in male Steller sea lions.

Bats of the genus Scotophilus are distributed throughout sub-Saharan Africa, parts of southern and Southeast Asia, a majority of the Indomalayan Islands, Reunion Island, and Madagascar. The genus is composed of 14 recognized species with seven distributed throughout sub-Saharan Africa including: (S. dinganii (A. Smith, 1833), S. leucogaster (Cretzschmar, 1830), S. nigritellus de Winton, 1899, S. nigrita (Schreber, 1774), S. nucella Robbins, 1983, S. nux Thomas, 1904, and S. viridis (Peters, 1852). The remaining species include four from southern and southeast Asia (S. celebensis Sody, 1928; S. collinus Sody 1936; S. heathi (Horsfield, 1831); S. kuhlii Leach, 1821), two on Madagascar (S. sp. nov. Goodman et al., in press; and S. robustus Milne-Edwards, 1881), and one endemic to Reunion Island (S. borbonicus (E. Geoffroy, 1803). The systematics and taxonomy of this genus have been controversial and continue to be confusing. The genus is plagued with problems in species definition and the systematic relationships among members of the genus are poorly understood. The major goal of this study was to use a molecular phylogenetic approach to clarify some of the controversy and confusion surrounding the members of this genus. Nucleotide differences from mtDNA and the Y chromosome were used to examine phylogenetic patterns within Scotophilus. Based on these data two new species of Scotophilus were identified. Phylogenetically, African Scotophilus were found to comprise a monophyletic group with S. nux as the most basal African taxon. Overall, the Asian S. kuhlii was the most basal taxon. A distant relationship was identified between S. kuhlii and S. heathi, the other Asian species examined. The multiple origins of Malagasy Scotophilus are apparent as the two Malagasy taxa in the study do not share a sister-group relationship. The large bodied S. nigrita is closely related to S. dinganii and the S. dinganii-like species all share a close relationship. S. nigrita has a S. dinganii-like mtDNA haplotype and a very distinct zfy haplotype, suggesting a possible hybridization event with a S. dinganii-like ancestor.

Les chromosomes sexuels subissent pendant la spermatogenèse de multiples modifications qui entrainent d’importantes variations dans le niveau d’expression des gènes qu’ils portent. Notamment, ils sont inactivés au cours de la méiose et la majorité reste réprimé tout au long de la spermiogenèse. Cette étude met en évidence l’existence de transcrits alternatifs particuliers de gènes sur le chromosome X et Y, dont les profils d’expressions témoignent de leur rôle au cours de ces deux phases de la spermatogenèse. Sur le chromosome X nous avons isolé, chez l’homme et chez la souris, trois gènes ubiquitaires (Uba1x, Prdx4, Atp11c) réactivés dans les spermatides via un transcrit alternatif exprimé de façon majoritaire dans les testicules. Le gène Prdx4 code, pour deux isoformes de protéines différentes par leur domaine N-terminal. Nous avons mis au point des anticorps spécifiques de chaque isoforme et nous avons démontré que, chez la souris, le transcrit réactivé est traduit dans les spermatides et produit une protéine dans un compartiment cellulaire distinct de l’autre isofome ubiquitaire. Un total de cinq mutations, affectant ces transcrits exprimés dans les spermatides, ont été retrouvées dans les gènes UBA1X et PRDX4 chez des hommes infertiles. Sur le chromosome Y chez la souris, nous avons étudié les gènes Zfy1 et Zfy2, deux homologues testicules spécifiques codant pour des protéines à doigt de zinc avec un long domaine d’activation. Zfy2, mais pas Zfy1, promeut l’élimination apoptotique des spermatocytes contenant un chromosome X univalent. Nous avons identifié un transcrit alternatif du gène testicule spécifique Zfy1 exprimé dans les spermatocytes et les spermatides. La protéine putative issue de ce transcrit, possédant un domaine acidique réduit de moitié qui pourrait être à l’origine des différences fonctionnelles entre les gènes homologues Zfy1 et Zfy2 au cours de la méiose murine. Chez l’homme, l’orthologue de ces gènes ZFY est ubiquitaire et nous avons montré qu’il produisait un transcrit alternatif testicule spécifique, codant une protéine avec le même domaine acidique raccourci que Zfy1. Nos données indiquent que ce transcrit alternatif est prédominant dans les spermatocytes et les spermatides chez l’homme et chez la souris. Ces résultats apportent la première évidence d’une fonction du gène ZFY au cours de la spermatogenèse chez l’homme et de son implication possible dans la fertilité masculine. / Sex chromosomes undergo many modifications during spermatogenesis, leading to dramatic variations in the expression levels of their genes. In particular, they are inactivated during meiosis with most genes remain silent throughout spermiogenesis. Our study describes specific alternative transcripts produced by X and Y chromosome genes, whose expression indicates roles in early spermatocytes (meiosis) and in spermatids (spermiogenesis). On the X chromosome, we have shown that three widely transcribed genes, Uba1x, Prdx4, and Atp11c, are reactivated in mouse and human spermatids via an alternative transcript that is expressed mainly in the testis. The Prdx4 gene codes two isoforms of the peroxiredoxin 4 that differ in their N-terminal domain. We have raised antibodies specific for each PRDX4 isoform and demonstrate, in mouse, that the reactivated transcript is translated in spermatids, producing a protein in a distinct cellular compartment from the ubiquitous isoform. Altogether, five mutations, affecting the spermatid-reactivated transcripts uniquely, of UBA1x and PRDX4, have been found specifically in our group of infertile men. On the mouse Y chromosome, we have studied Zfy1 and Zfy2, nearly identical testis specific zinc finger genes with long acidic (activation) domains. Zfy2, but not Zfy1, promotes the apoptotic elimination of spermatocytes with an unpaired X chromosome. We have identified an alternatively spliced transcript of Zfy1 that lacks half the acidic domain, and could explain the functional difference between Zfy1 and Zfy2. In human, the ZFY gene is widely transcribed, but we show that ZFY produces a testis specific variant transcript, encoding the same short acidic domain as Zfy1. Our data indicate that the alternative transcripts predominate in spermatocytes and spermatids, in both human and mouse. This provides the first evidence that human ZFY may play a conserved role during spermatogenesis, and contribute to human male fertility.

Molecular techniques, particularly noninvasive genetic sampling (NGS) and nondestructive sampling (NDS), are increasingly being used as tools to study the ecology of free-ranging mammals. A specific application of these methods is the molecular sexing of species for which external sex differentiation is challenging. Star-nosed moles (Condylura cristata) are a little-studied species in which females possess a peniform clitoris making them externally indistinguishable from males. To my knowledge, no studies have employed NDS to study any aspect of their ecology. I therefore sequenced fragments of one X-chromosome (Zfx) and two Y-chromosome (Sry and Zfy) genes from known-sex specimens, and designed species-specific primers to co-amplify these loci from hair, claw and fecal samples of 16 star-nosed moles. I found all tissue types were highly (90-100%) reliable for sex determination. I envision that this NDS method will facilitate future capture-and-release studies on the natural history and social structure of this fascinating, semi-aquatic mammal.

I developed and tested a protocol for determining the sex of individual pinnipeds using the sex-chromosome specific genes ZFX and ZFY. I screened a total of 368 seals (168 crabeater, Lobodon carcinophagus; 159 Weddell, Leptonychotes weddellii; and 41 Ross, Ommatophoca rossii) of known or unknown sex and compared the molecular sex to the sex assigned at the time of collection in the Ross and Amundsen seas, Antarctica. Discrepancies ranged from 0.0% - 6.7% among species. It is unclear, however, if mis-assignment of sex occurred in situ or in the laboratory. It also is possible, however, that the assigned morphological and molecular sex both are correct, owing perhaps to developmental effects of environmental pollution. I sequenced a portion (ca 475 bp) of the mitochondrial control region of Weddell seals (N = 181); crabeater seals (N = 143); and Ross seals (N = 41). I resolved 251 haplotypes with a haplotype diversity of 0.98 to 0.99. Bayesian estimates of Θ from the program LAMARC ranged from 0.075 for Weddell seals to 0.576 for crabeater seals. I used the values of theta to estimate female effective population sizes (NEF), which were 40,700 to 63,000 for Weddell seals, 44,400 to 97,800 for Ross seals, and 358,500 to 531,900 for crabeater seals. Weddell seals and crabeater seals had significant, unimodal mean pairwise difference mismatch distributions (p = 0.56 and 0.36, respectively), suggesting that their populations expanded suddenly around 731,000 years ago (Weddell seals) and around 1.6 million years ago (crabeater seals). Both of these expansions occurred during times of intensified glaciations and may have been fostered by expanding pack ice habitat. Autosomal microsatellite based NEs were 147,850 for L. Weddellii, 344,950 for O. rossii, and 939,600 for L. carcinophagus. I screened one X-linked microsatellite (Lw18), which yielded a larger NE estimate for O. rossii than the other two species. Microsatellite NE estimates are compared with previously published mitochondrial NE estimates and this comparison indicates that the Ross seal may have a serially monogamous system of mating. I find no sign of a recent, sustained genetic bottleneck in any of the three species.