MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

BIOLOGY

SECTION 1. BIOLOGICAL BASES OF HUMAN VITAL ACTIVITY

1.4. ONTOGENETIC LEVEL OF LIFE ORGANIZATION

1.4.2. Fundamentals of Human Genetics

Main Principles of the Chromosomal Theory of Heredity

The chromosomal theory of heredity was formulated and experimentally proven in Experiments on the fruit fly (Drosophila melanogaster) conducted in 1910-1925 by the American geneticist T. Morgan and his school - A. Sturtevant, H. Muller, and C. Bridges. Its main principles are:

1. Genes are located in Chromosomes. Genes situated in the same chromosome form a linkage group. The number of Gene linkage groups in each species of Organism is equal to the haploid chromosome number.

2. Each gene occupies a specific site (locus) in the chromosome. Genes are arranged linearly along the length of the chromosome (one after another).

3. Allelic genes occupy specific and identical loci on homologous chromosomes.

4. Mutual exchange of segments between homologous chromosomes - Crossing Over - may occur during Meiosis.

5. Each biological species is characterized by a specific set of chromosomes - the karyotype.

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Thomas Hunt Morgan (1866-1945)

Significance: the chromosomal theory of heredity is a fundamental theory of genetics, according to which material factors are extended from animal research to The Study of microorganism genomes (primarily pathogens). These works will be of paramount importance in combating infectious diseases in humans, animals, and plants. A new science has emerged - Proteomics, which deals with the inventory of Proteins using a combination of Methods: two-dimensional Electrophoresis, mass spectrometry, and bioinformatics. Using these methods, it is possible to create a protein map of any biological material, which represents the phenotypic expression of The Genome of a Cell, tissue, or organ. Structure/19.html">The Importance of information regarding proteins is determined by the fact that proteins perform all major biological Functions.



Last update: 08/08/2026

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