醫(yī)學(xué)遺傳學(xué))11人類染色體畸變(已修改)
2025-01-16 04:39 本頁面
【正文】 Medical Geics 末代沙皇尼古拉二世的公主斯塔西婭 安娜 安德森 1956電影”真假公主” Medical Geics 10 人類染色體畸變 chromosome aberration Medical Geics Any type of change in the chromosome structure or number (deficiencies, duplications, translocations, inversions, etc.). Medical Geics Although it can be a mechanism for enhancing geic diversity, such alterations are usually fatal or illadaptive, especially in animals. Medical Geics 1. factors inducing chromosome aberration A. Ionizing radiation Ionizing radiation produces rearrangements of the genome. Medical Geics Medical Geics When irradiation occurs during the G0/G1 phase of the cell cycle, largescale rearrangements appear as exchangetype chromosome aberrations at the next mitosis. Such aberrations can alter cellular phenotypes, and are important in various areas of biology: Medical Geics Analyzing chromosome aberrations helps characterize repair/misrepair pathways involved in the processing of DNA damage. Ionizing radiation has some unique features as a probe of such pathways. Compared to other genotoxic agents, it produces copious quantities of DNA double strand breaks (DSBs), and its timing can be controlled more accurately. Medical Geics Moreover, initial radiation damage has a discrete, stochastic character that can be modulated by using different kinds of radiation (. a particles versus xrays) having different ionization densities. Medical Geics The spectrum of different radiationinduced chromosome aberrations is informative about the geometry of chromosomes during interphase, and vice versa. Medical Geics B. chemical mutagen A kind of substances, such as drugs or toxins ,that causes chromosomal aberrations of living anisms, or increase the rate of mutation. Medical Geics Drug ? antitumor drug（ 抗腫瘤藥物） 環(huán)磷酰胺、氮芥、白硝安（馬利蘭）、甲氨喋呤、阿糖胞苷等抗癌藥物 ? Tocolysis（子宮收縮抑制劑） ? drug which prevent pregnancy reaction(預(yù)防妊娠反應(yīng)的藥物 ) ? antiepileptic 苯妥英鈉可引起人淋巴細(xì)胞多倍體細(xì)胞數(shù)增高 Medical Geics ? agricultural chemicals Some agricultural chemicals can induce chromosome aberration, like phosphate pesticide. Medical Geics
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