BOT 103 MSc I CH 1 CYTOGENETICS : DEFINATION, HISTORY AND APPLICATION IN BIOLOGY
BOT 103 MSc I CYTOGENETICS
&
MOLECULAR BIOLOGY
CH 1. Cytogenetics : Definition, history and application in Biology
Prof. Dr. Sadhana Nikam
M.Sc , B.Ed, PGDDE, Ph.D
Definition of
cytogenetics :
A branch of biology which deals with
the study of heredity and variation by the methods of both cytology
and genetics is called Cytogenetics.
* It is also a part of cell biology
or cytology.
*It is concerned with how the
chromosomes relate to cell behaviour, particularly during mitosis and meiosis.
*Techniques used include
karyotyping, analysis of G-banded chromosomes, other cytogenetic banding
techniques.
* molecular cytogenetics such as
fluorescent in situ hybridization (FISH) and comparative genomic hybridization
(CGH).
1.Robert Hooke
discovered the cell
in sections of
cork in 1665.
2.M.J.Schleiden and T.S. Schwann
formulated the cell
theory in 1838.
3. J.E.Purkinje &
Hugo von Mohl proposed the
name protoplasm in
1839.
4.Chromosomes were first observed in
plant cells by Karl Wilhelm von Nägeli in 1842.
5. Robert Brown
discovered the nucleus
in 1831.
6. Gregor Mendel
formulated the laws
of heredity in
1866.
7. Balbiani discovered
giant salivary gland
chromosomes in 1881.
8. Walther Flemming
coined the term mitosis in 1882.
9.The name chromosomes was coined by another German
anatomist, von Waldeyer in 1888.
10. C. benda gave
the name mitochondria
in 1898.
11. Camillo Golgi
discovered Golgi apparatus
in 1898.
12.The next stage took place after
the development of genetics in the early 20th century, when it was confirmed that the set of chromosomes (the karyotype)
was the carrier of the genes.
13.Levitsky define the karyotype as the phenotypic
appearance of the somatic chromosomes, in contrast to their genic contents.
14.In 1912, Hans von Winiwarter
reported 47 chromosomes in spermatogonia and 48 in oogonia, concluding an XX/XO
sex determination mechanism.
15.Painter in 1922 was not certain whether the diploid number
of humans was 46 or 48, at first favoring 46.
16.He revised his opinion later from
46 to 48, and he correctly insisted on humans having an XX/XY system of
sex-determination.Considering their techniques, these results were quite
remarkable.
17.It took until 1956 for it to be generally
accepted that the karyotype of man included only 46 chromosomes.
Q. Give Applications
of Cytogenetics ?
Applications of Cytogenetics
:
1.Diagnosis of various human diseses at molecular level.
2. Detection of drug effectivity.
3. Detection of drug toxicity.
4. In research as effective
cytogenetic tool.
5. For improvement of diseases
at diagnostic stage.
6. For conformation of diseases
at primary stage.
7.Cytogenetic techniques are useful in
cancer management, to detect somatic genetic changes in the neoplastic cells.
8.Cytogenetics help to
understand various complicated
life activities as
metabolism, growth, differentiation, heredity, evolution at cellular & molecular level.
9. It help
to analyse chemical &
physiochemical analysis of presence
of carbohydrates, lipids, proteins,
nucleic acid & other inorganic compound.
10. Cytological concept
of genetics is useful to know Weismann theory of
germplasm, Mendel’s laws
& Concept of
gene.
11. Cell physiology help to
know physiological activities at cellular level.
12.
Molecular Biology help to
know ultrastructure, genetic code &
protein synthesis.
13. It provide
cytological support to
taxonomic position of
any species.
14. Cytogenetics help
to know ecological
habitat & geographical
distribution related to
chromosome number in
cytoecology.
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