THE CHEMICAL COMPOSITION OF ISOLATED CHROMOSOMES

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Chromosomes are complex structures composed of nucleoproteins.
• Understanding chromosome composition is crucial for comprehending genetic organization and function.

Purpose of the Study:

• To investigate the biochemical composition and structural properties of isolated lymphocyte chromosomes.
• To elucidate the role of different chromosomal fractions in chromosome morphology and gene arrangement.

Main Methods:

• Fractionation of isolated lymphocyte chromosomes using 1 M sodium chloride (NaCl).
• Analysis of the biochemical composition (nucleic acids and proteins) of the separated fractions.
• Microscopic observation to assess structural characteristics.

Main Results:

• Chromosomes yielded two nucleoprotein fractions: a soluble desoxyribonucleohistone fraction (90-92% of mass) and an insoluble residual chromosome (8-10% of mass).
• The soluble fraction contains most of the nucleic acid and is responsible for staining.
• The insoluble residual chromosome, a coiled thread, provides the chromosome's form and is implicated in gene order.

Conclusions:

• The desoxyribonucleohistone fraction is primarily responsible for chromosome staining.
• The residual chromosome, a proteinaceous linear structure, dictates chromosome morphology and is proposed as the basis for the linear gene order.