NEET2026BiologyChapterActual
Which of the following best describes the genetic basis of traits like human skin colour and height, which show a continuous gradient of phenotypes in a population?
Options
- AThey are controlled by a single gene exhibiting multiple allelism.
- BThey are controlled by three or more genes where the effect of each allele is additive.
- CThey are controlled by a single gene that influences multiple distinct phenotypic traits.
- DThey are controlled by a pair of co-dominant alleles that express equally.
Correct answer
B. They are controlled by three or more genes where the effect of each allele is additive.
Step-by-step solution
Traits like human skin colour and height show a continuous gradient of phenotypes in a population. This type of inheritance is known as polygenic inheritance. In polygenic inheritance, a single trait is controlled by three or more genes. The inheritance pattern is characterized by the additive effect of each dominant allele, meaning the phenotype reflects the total number of dominant alleles present. Option (A) describes multiple allelism, where more than two alleles exist for a single gene in a population. Option