The Himalayan Mountain range encompasses an unparalleled landscape featuring some of the planet’s highest peaks, including Mount Everest. In the heart of this massive orographic barrier lies Nepal, sandwiched in the historically geostrategic position between the Tibetan plateau to the north and India in the south. Until recently, Nepalese and Tibetan populations remained poorly characterized genetically, partly because of their inaccessible geographical locations. In the present study, the genetic diversity of these two Himalayan populations is evaluated using different marker systems, including mitochondrial DNA (mtDNA) and Short Tandem Repeats (STRs) in the autosomes as well as on the Y-chromosome (Y-STR). While autosomal STRs are distributed throughout the genome and are biparentally inherited, the Y-chromosome and mtDNA are haploid markers and provide the paternal and maternal histories of the population, respectively. Fifteen autosomal STR loci were typed in 341 unrelated individuals from three Nepalese populations (188), namely Tamang (45), Newar (66) and Kathmandu (77), and a general collection from Tibet (153). These samples were also sequenced for the mtDNA control region and all of them were subsequently assigned to 75 different mtDNA haplogroups and sub-haplogroups by screening their diagnostic sites in the coding region using Restriction Fragment Length Polymorphism analysis and/or sequencing, thus achieving an unprecedented level of resolution. The results from the autosomal and mtDNA data suggest a Northeast Asian origin for the Himalayan populations, with significant genetic influence from the Indian subcontinent in Kathmandu and Newar, corroborating our previous Y-chromosome study. In contrast, Tibet displays a limited Indian component, suggesting that the Himalayan massif acted as a natural barrier for gene flow from the south. The presence of ancient Indian mtDNA lineages in Nepal implies that the region may have been inhabited by the earliest settlers who initially populated South Asia. In addition, seventeen Y-STR loci were analyzed in 350 Tibetan males from three culturally defined regions of historical Tibet: Amdo (88), Kham (109) and U-Tsang (153). The results demonstrate that the 17 Y-STR loci studied are highly polymorphic in all the three Tibetan populations examined and hence are useful for forensic cases, paternity testing and population genetic studies.

La mitose permet la multiplication des cellules, contribuant ainsi à générer de nouveaux organismes unicellulaires, ou à construire des organismes multicellulaires. Pendant la mitose, le génome répliqué de la cellule mère est réparti entre les deux cellules filles. Les erreurs survenant lors de la répartition peuvent mener à l’aneuploïdie, une caractéristique de certaines maladies développementales dont les cancers. La fidélité de la répartition des chromatides sœurs dépend du fuseau mitotique, un réseau bipolaire de microtubules qui dirigent les chromosomes via leurs interactions avec les kinétochores assembles sur les chromatides sœurs. Ces interactions mènent à l’alignement des chromosomes, et à leur biorientation. Les chromatides sœurs sont alors attachés à des microtubules .manant des pôles opposés du fuseau. La ségrégation des chromatides sœurs a alors lieu en anaphase, et simultanément le fuseau central est assemblé entre les deux jeux de chromosomes. Cette structure composée de microtubules contribue à la ségrégation des chromatides sœurs en spécifiant la localisation et en favorisant l’ingression du sillon de division cellulaire. Pendant ma thèse, j’ai étudié les fonctions d’un ensemble de protéines du kinétochore, BUB-1, HCP-1/2CENP-F et CLS-2CLASP, lors de la mitose dans les zygotes de C. elegans. En combinant des approches de génétique et de vidéo-microscopie, j’ai montré que ces protéines participent à l’alignement et à la ségrégation des chromosomes. En particulier, BUB-1 contribue à l’alignement des chromosomes en accélérant l’attachement des microtubules aux kinétochores, tout en contrôlant la conformation et la maturation de ces attachements. Ces activités dépendent du recrutement de HCP-1/2 et CLS-2 par BUB-1, mais aussi du complexe RZZ et de la dynéine, ainsi que d’une activité de BUB-1 inhibant le recrutement du complexe SKA aux kinétochores. De plus, j’ai montré que BUB-1, HCP-1/2 and CLS-2 contribuent à l’assemblage des microtubules du fuseau central via l’activité polymérase de CLS-2. Cette fonction dépend du pré-recrutement de ces protéines aux kinétochores en métaphase, en aval de KNL-1, révélant une nouvelle fonction pour les kinétochores dans l’assemblage du fuseau central. Ce travail identifie donc des fonctions versatiles pour ces protéines, les plaçant comme des gardiennes majeures de l’intégrité génétique / Mitosis is a process by which cells multiply, contributing to the generation of new unicellular organisms, or the construction of multicellular organisms. During mitosis, the daughter cells inherit an identical copy of the mother cell’s replicated genome. Errors in genetic material distribution can lead to aneuploidy, a hallmark of developmental diseases including cancer. The accurate segregation of sister chromatids relies on the mitotic spindle, a bipolar network of microtubules that governs chromosome movements by interacting with the kinetochores assembled on sister chromatids. This drives chromosome alignment at the spindle equator, and chromosome bi-orientation meaning that sister kinetochores are connected to opposite spindle poles, laying the ground for sister chromatid segregation during anaphase. Once segregation has initiated, the microtubule-based central spindle is assembled between the two sets of chromosomes. This structure contributes to sister chromatid segregation, by specifying the location and favoring the ingression of the cytokinesis furrow. During my thesis, I have studied the functions of a subset of conserved kinetochore proteins called BUB-1, HCP-1/2CENP-F and CLS-2CLASP, during mitosis in C. elegans zygotes. By combining genetics and live imaging, I have shown that these proteins are involved both in chromosome alignment and segregation. In particular, I have shown that BUB-1 contributes to chromosome alignment by accelerating the establishment of end-on kinetochore-microtubule attachments, while controlling the conformation and maturation of these attachments. These activities rely on BUB-1’s downstream partners HCP-1/2CENP-F and CLS-2CLASP, but also on the RZZ complex and dynein, as well as an activity for BUB-1 in inhibiting the recruitment of the SKA complex. Additionally, I have shown that BUB-1, HCP-1/2CENP-F and CLS-2CLASP contribute to central spindle microtubule assembly, via CLS-2CLASP’s polymerase activity. This function relies on the prior kinetochore recruitment of these proteins during metaphase by the kinetochore scaffold protein KNL-1, revealing a new function for the kinetochore in central spindle assembly. Together, this work identifies versatile functions for this subset of conserved kinetochore proteins, making them major safe-keepers of genomic integrity

The aim of this diploma thesis is using cartesian genetic programming on design image filters and creating basic structure for implement diferent type of problems. Genetic programming is rapidly growing method, which often using for solve dificult problems. This thesis analyze basic principle, way of application and implementing this method to design filters. Result of this thesis is program realize design filters define by specific parameters, overview of implementig method and achieve summary from this sphere.

The unique chromosome biology of the fungus fly Sciara coprophila has fascinated investigators for over 80 years. Male meiosis exhibits a monopolar spindle, nonrandom segregation of imprinted chromosomes and nondisjunction of the X chromosome. The unusual mechanism of sex determination requires selective elimination of X chromosomes in embryogenesis. Super-numerary (L) chromosomes are also eliminated from the soma during early cleavage divisions. Distinctive DNA puffs on the larval salivary gland chromosomes are sites of DNA amplification. As a foundation for future genome studies to explore these many unusual phenomena, we have used DNA-Feulgen cytophotometry to determine genome size from hemocyte nuclei of male (X0) and female (XX) larvae and adults. The DNA content of the X chromosome is ∼0.05 pg DNA and the autosomal complement is ∼0.45 pg DNA. Measurements of DNA levels for individual sperm from adults showed that the DNA contribution of the germ line-limited (L) chromosomes constitutes as much as 35% of the DNA of the male gamete. A parallel study using Sciara ocellaris, a related species lacking L chromosomes, confirmed the presence of two X chromosomes in the sperm of this species.

京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第21400号 / 生博第401号 / 新制||生||53(附属図書館) / 京都大学大学院生命科学研究科高次生命科学専攻 / (主査)教授 松崎 文雄, 教授 石川 冬木, 教授 松本 智裕 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

The ubiquitin-proteasome proteolysis pathway is responsible for the degradation of abnormal and short-lived proteins to regulate many important biochemical activities in eukaryotes. By employing affymetrix microarray analysis, we have identified a novel ubiquitin ligase E3 gene GhRING2 that is expressed differentially between two G. hirsutum lines - Texas Marker-1 and Chromosome Substitution Line CS-B25. The complete GhRING2 gene sequence was obtained by genomic and cDNA walking. The expression of GhRING2 in cotton fiber is developmentally regulated, suggesting that the ubiquitin-proteasome pathway may regulate cotton fiber growth and development. Using a yeast two-hybrid assay GhRING2 was found to interact with a PROTODERMAL FACTOR1 (GhPDF1) protein. GhPDF1 is expressed preferentially in immature ovules and fiber initials and the gene has been suggested to play a role in cell fate determination and fiber development. Pull down and plasmid swap assays were employed to confirm this interaction.

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