Question

'Genic balance theory' was forwarded by

• A. Lillie
• B. Crew
• C. Lederberg and Tatum
• D. C B Bridges

Answer 1

Answer: (D)

C B Bridges

Genic balance theory was given by Calvin Bridges in the year 1926. It states that sex is determined by the genic balance or ratio between X-chromosomes and autosome genomes. It considers the fact that every individual contains genes for both maleness and femaleness in its genotype. The sex chromosomes are not the only factor to determine the sex rather autosomes play an important role. He observed in Drosophila that the genic ratio X /А of 1.0 produces fertile females while a genic ratio (X /А) of 0.5 forms a male fruitfully.

So, the correct answer is option D.