日時：１１月１６日（金）１６：３０－１８：００
場所：理学部２号館４０２号室
演題：The Ancestral Karyotype of Primates and the Origin of the Human Genome
講演者：Roscoe Stanyon 先生 ：Dipartimento di Biologia Animale e Genetica Laboratori di Antropologia
（フィレンツェ大学人類学部門教授 ロスコー スタニョン）
講座区分：人類学談話会
要旨
Evolution is still the single most important theory of biology. In the past, knowledge of evolution was based on comparative anatomy and
paleontology, but over the last half century the study of evolution has become evermore the evolution of genomes. One of the major tenets
of Darwin's theory of evolution is that all form of life are connected by descent from common ancestors. Comparative genomics allow speculation about the content of the genome of ancestral species. Attempt at reconstructing ancestral karyotypes dates back to the earliest investigations of comparative cytogenetics when hypotheses were framed only in terms of the diploid number (2n) and the number of chromosome arms (fundamental number, FN). In the 1970s differential staining methods (chromosome banding) were introduced and between species similarities in banding patterns were found. In closely related species similarities in chromosome banding were a good guide to gene content, but in species characterized by numerous rearrangements banding similarities were more difficult to discover
and were no guarantee of homology. Over the last 15 years molecular cytogenetics has revealed the global genome composition of almost 50
species of primates based on homologous DNA content. Fluorescence in situ hybridization (FISH) using DNA probes specific to each entire
human chromosome (chromosome painting) has been and remains the method of choice. Flow activated chromosome sorting (FACS) of non-human
primate chromosomes has refined the method (reciprocal chromosome painting) allowing the delineation of sub-chromosomal homology and
definition of breakpoints. However, there are limitations to chromosome painting because this method deals primarily with interchromosmal rearrangements (translocations) and intrachromosomal rearrangments such as inversion, duplications and deletions escape detection. FISH of bacterial artificial chromosomes (BACs) can help reveal intrachromosomal rearrangments and determine marker order. Data on chromosomal homology and marker order in primates are now sufficient to allow an accurate reconstruction of the ancestral karyotype of primates including centromere position and marker order. We can determine the major steps over the last 90 million years leading to the ancestral karyotypes of each major branch of primates and the formation of each human chromosome. These reconstructions provide insight into evolutionary forces that have sculpted the genomes of extant species.
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