MINISTRY OF EDUCATION AND SCIENCE OF UKRAINE

NATIONAL AVIATION UNIVERSITY

Institute of ecological safety

DEPARTMENT OF BIOTECHNOLOGY

Homework

Methods of cytogenetics

Student : Inna Yatsenko

Group IES 204

Instructor: Vasylchenko O. A.

Kyiv 2012

Plan

1. Introduction.

2. History

3. Caryotyping by differential staining

4. Method of standard cytogenetic studies (SCS)

5. FISH method (Fluorescence in situ Hybridization)

5.1. Principle of the method of fluorescence in situ hybridization

5.2. Key benefits of FISH-analysis

6. Other methods of cytogenetic researchers

• Centrifugation

• Methods of "tracer" or autoradiography

• Method of cell culture

7. Conclusion.

8. References.

1.Introduction

Cytogenetics (from cyto ... and genetics), the science that studies the laws of heredity in relation to the structure and functions of different subcellular structures. The main subject of research cytogenetics - chromosome morphology, structural and chemical organization, function, and behavior in dividing and nondividing cells. Cytogenetics as a border science uses methods of Genetics and Cytology, and is closely related to the sections of the sciences - molecular genetics, cytochemistry, karyotype, etc. Karyosystematics subdivided into general cytogenetics, which studies the common cellular basis of heredity, and cytology of plants, animals and humans.

In the process of cytogenetics were obtained cytological study the phenomenon of splitting, independent distribution, cohesion genes and crossing over. In studying the behavior of chromosomes in meiosis revealed that the splitting of characters in offspring is provided a process of conjugation of chromosomes, which are due to differences in one meiotic division to different poles of the cell gamete contains a single (haploid) set of them instead of double (diploid), present in the somatic cells. Independent distribution of genes located in the non-homologous chromosomes, due to the free recombination in meiosis, the chromosomes received from the father and mother. Confirmed that linked genes can be violated in the process of crossing the exchange segments between homologous chromosomes, and this exchange leads to recombination of genetic material.

At the cytogenetic analysis of the process of conjugation of chromosomes found that a violation of conjugation leads to incorrect chromosome segregation and the formation of gametes with a set of chromosomes, not multiple haploid, ie, aneuploidy, and this causes a decrease in fertility or infertility in hybrids (especially remote) of plants and animals.

2. History

The history of human cytogenetics can be divided into three periods. The first covers the period from the last century to the mid 50's and is now a purely historical interest. They were looking methodological approaches to obtain preparations of human chromosomes remarkable for their perseverance and hard work cytologists then (AG Andres, 1934). Although our cytogenetics AG Andres and M.S. Navashin were correctly described the first 10 pairs of large chromosomes, but was not reliably established even the total number of chromosomes in human cells. Remained unknown and their morphology.

     The second period, which began work Tjio and Levan in 1956, was characterized by the emergence and rapid development of modern human cytogenetics. Pretty soon were developed all the basic instructional techniques chromosomal analysis, obtained basic information about the human karyotype, the main features of the structure and functioning of its normal chromosomes. It was during this period originated Medical cytogenetics, which opened the new field of human pathology that is caused by changes in the number or structure of chromosomes.

     The third period of human cytogenetics began in the 70's. It can rightly be considered the beginning of the current stage in the development of the science of human cytological basis of heredity. Several methodological innovations provided cytogenetics transition to a qualitatively new level. The opportunity to study individual human chromosomes and even their plots. This immediately raised to a new level of medical cytogenetics. It was possible to explore the complex morphology, function, structure and chemical characteristics nadmoleku-polar organization of human chromosomes. The development in these years, methods of genetic mapping of human chromosomes has provided solutions very difficult task - creating genetic maps of chromosomes.

     Thus, the modern human cytogenetics is a wealth of factual material, extensive independent field of human genetics. Now the problem of identification of all elements of the human karyotype analysis at the stage of mitosis solved by applying differential colorings chromosomes.

     Chromosomes as individual structures become available for study after a significant shortening and thickening that they experience during the preparation of the cells to divide. For somatic cells that division is mitosis for generative - first mitosis, and meiosis.