In which year did an American cytogeneticist named Joe Hin Tjio publish a research finding that defined 2n = 46 as the exact number of human chromosomes?

Question

Question

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SSC CGL 2023 Tier-I Official Paper (Held On: 20 Jul 2023 Shift 4)

Answer 1

The correct answer is 1956.

Key Points

Joe Hin Tjio was an American cytogeneticist who published a research finding in the year 1956 that defined 2n = 46 as the exact number of human chromosomes.
Tjio's research finding was based on his extensive experiments involving the counting of chromosomes in human cells using microscopy and other techniques.
The discovery of the exact number of human chromosomes was a landmark achievement in the field of genetics and had significant implications for the study of human diseases and genetic disorders.

Additional Information

Cytogenetics is the branch of genetics that studies the structure and function of chromosomes and their relationship to cell behavior and inheritance.
The discovery of the exact number of human chromosomes was a collaborative effort that involved several scientists, including Albert Levan, who worked with Tjio to confirm the finding.
(1950) is close to the actual year of Tjio's appointment at the University of Lund in Sweden, where he began his research on human chromosomes. Option 2 (1952) is also close to the actual year when Tjio first observed and counted human chromosomes under the microscope. However, neither of these options represents the year when Tjio published his research findings. Option 4 (1960) is too late as it comes after several other significant discoveries had already been made in the field of cytogenetics.