醫(yī)學遺傳學英文教學課件：IntroductionAA

1、Introduction Medical Genetics Emphasis vThe laws of heredity vTypes of genetic diseases vLyon hypothesis vMutation Concept Medical Genetics is the application of genetics to medical practice. Genetic diseases are the diseases which are due to altered genetic materials (genes or chromosomes). v1865,

2、Mendel G Experiments in Plant Hybridization 1. The Laws of Genetics Experiments in Plant Hybridization Mendels first law of genetics (Law of segregation) Mendels second law of genetics (Law of independent assortment) v1865, Mendel G 1. The Laws of Genetics vLaw of segregation 1. The Laws of Genetics

3、 Y Yy yY yY y13 Y Yy y Y y vLaw of segregation 1. The Laws of Genetics Parental Cross F1 Phenotype F2 Phenotypic Ratio F2 Ratio Yellow Green Seeds Yellow 6022 Yellow : 2001 Green 3.01:1 Round Wrinkled Seeds Round 5474 Round : 1850 Wrinkled 2.96:1 Red White Flowers Red 705 Red : 224 White 3.15:1 Tall

4、 Dwarf Plants Tall l787 Tall : 227 Dwarf 2.84:1 The hereditary determinants are called hereditary factor (gene). Each parent has a gene pair in each cell. One member of the gene pair segregates into a gamete, thus each gamete only carries one member of the gene pair. Gametes unite at random and irre

5、spective of the other gene pairs involved. vLaw of segregation 1. The Laws of Genetics During gamete formation each member of the allelic pair separates from the other member to form the genetic constitution of the gamete. Cytogenetic basis Disjunction of homologous chromosomes in meiosis I. vLaw of

6、 segregation 1. The Laws of Genetics vLaw of independent assortment P F1 F2 1. The Laws of Genetics 315:101:108:32 9:3:3:1 9 : 3 : 3 : 1 vLaw of independent assortment 1. The Laws of Genetics During gamete formation the segregation of the alleles of one allelic pair is independent of the segregation

7、 of the alleles of another allelic pair. Cytogenetic basis Random assortment of non-homologous chromosomes in meiosis I. vLaw of independent assortment 1. The Laws of Genetics v1910, Morgan TH normal n = 60 200; pre-mutation n = 200 230; full-patient 4. Mutation 4.3. Dynamic Mutation vHuntington disease (CAG)n 100 38 40 26 27 11 14 2 4. Mut