Question

According to Mendel's theory of inheritance, traits are always controlled by______

• A. A blending of parental 'essences'
• B. Single genes
• C. Multiple genes
• D. Environmental influences

Hint:

Mendel's work represents "particulate inheritance" where genes retain their identity across generations.
This is represented in his laws by the behavior of single genes containing dominant and recessive alleles.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Gregor Mendel, the father of modern genetics, formulated the laws of inheritance through his hybridization experiments on garden pea (Pisum sativum).
Mendel proposed that traits are inherited as discrete, non-blending units.

Step 2: Detailed Explanation:
Before Mendel, the prevalent theory of inheritance was "blending inheritance," which claimed that parental traits mixed together like paint in the offspring (e.g., a red flower and a white flower blending to produce pink).
Mendel disproved this by showing that inheritance is particulate.
He proposed that traits are controlled by discrete "factors" (which are now called genes) that exist in alternative forms called alleles.
In his classical monohybrid studies, each trait he studied (such as plant height, seed shape, or seed color) was controlled by a single gene showing a clear dominant-recessive relationship.
Although modern genetics recognizes complex inheritance patterns (like polygenic inheritance, epistasis, and environmental interactions), Mendel's original classical theory of inheritance was based on the premise that distinct individual traits are controlled by single genes containing discrete alleles.

Step 3: Final Answer:
According to Mendel's classical theory, traits are controlled by single genes.