Original positions of the chromosome theory of inheritance by Т. Morgan.

Date: 2015-10-07; view: 462.

THE BASIC THEORETICAL ITEMS OF INFORMATION

STUDY 27

Theme:CYTOLOGICAL basis of heredity. Chromosomes of eukaryotic cells. Bonded (LINKED) inheritance. Original positions of the theory Т. Morgan. Impairment of cohesion. Genetics of sex.

1. The MEANING of the THEME. The study of cytological bases of heredity allows more deeply to understand the laws of originating of normal living process of cell and organisms, promotes introduction in practice of new methods of prophylactic, diagnostics and treatment of hereditary diseases of the human being.

2. PURPOSE of STUDY. General: To receive representation about cytological basis of heredity, chromosomes of eukaryotic cells, bonded inheritance, original positions of the theory Т. Morgan, impairment of genes' cohesion, and genetics of sex.

3. The CONCRETE PURPOSES of STUDY:

3.1. To be able to describe the chromosomes of eukaryotic cells.

3.2. To be able to explain the laws of bonded inheritance.

3.3. To be able to explain the laws of sex heredity.

Tomas Morgan and his scientific school created the chromosome theory of heredity. Here are the main points of the theory.

a. Genes are laid within chromosomes. Different chromosomes contain different number of genes. Kit of genes in each non-homologues chromosome is unique.

b. Each gene takes its own place that named locus. Genes are situated along the chromosome single-line. Allele genes take identical locuses of homologous chromosome.

c. Genes of one chromosome make a group of traction. Due to the traction take place joint inheritance of some characters.

d. Between two homologous chromosomes occurs an exchange of genes (crossing over). Probability of crossing over is straight proportional of distance between genes.

e. Each biological species has o specific kit of genes that named karyotype.