医学遗传学人类染色体畸变

Medical Genetics
Although it can be a mechanism for enhancing genetic diversity, such alterations are usually fatal or illadaptive, especially in animals.
Medical Genetics
The spectrum of different radiation-induced chromosome aberrations is informative about the geometry of chromosomes during interphase, and vice versa.
Medical Genetics
Moreover, initial radiation damage has a discrete, stochastic character that can be modulated by using different kinds of radiation (e.g. a -particles versus x-rays) having different ionization densities.
Medical Genetics
10 人类染色体畸变 chromosome aberration
Medical Genetics
Any type of change in the chromosome structure or number (deficiencies, duplications, translocations, inversions, etc.).
Medical Genetics
When irradiation occurs during the G0/G1 phase of the cell cycle, large-scale rearrangements appear as exchange-type chromosome aberrations at the next mitosis. Such aberrations can alter cellular phenotypes, and are important in various areas of biology:
Medical Genetics
B. chemical mutagen
A kind of substances, such as drugs or toxins ,that causes chromosomal aberrations of living organisms, or increase the rate of mutation.
苯妥英钠可引起人淋巴细胞多倍体细胞数 增高
Medical Genetics
• agricultural chemicals Some agricultural chemicals can induce chromosome aberration, like phosphate pesticide.
Medical Genetics
• Industrial poisons
苯、甲苯、铝、砷、二硫化碳、氯丁二稀、 氯乙烯单体
Medical Genetics
• Food additive
Preservative(防腐剂),pigment(色素),AF2(硝基呋喃基糖酰胺),benzosulfimide(环己基 糖精)。
Medical Genetics
C biological mutagen
• toxoid sterigmatocystin(杂色曲霉素),
Flavacin(黄曲霉素), clavacin(棒曲霉素)等 • virus
German measles virus(风疹病毒), (hepatovirus)乙肝病毒, Measles virus(麻
Medical Genetics
1. factors inducing chromosome aberration
A. Ionizing radiation
Ionizing radiation produces rearrangements of the genome.
Medical Genetics
疹病毒), cytomegalovirus(巨细胞病毒)
Medical Genetics
D Maternal age
Down综合征与母亲年龄
Medical Genetics
2. chromosБайду номын сангаасmal aberrations
A. chromosome numerical aberration
Numerical aberration is a change in the number of chromosomes from the normal number characteristic of the human beings.
Medical Genetics
Drug • antitumor drug（抗肿瘤药物）
环磷酰胺、氮芥、白硝安（马利兰）、甲 氨喋呤、阿糖胞苷等抗癌药物
• Tocolysis（子宫收缩抑制剂） • drug which prevent pregnancy
reaction(预防妊娠反应的药物) • anti-epileptic
Medical Genetics
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.