Heredity and Species Constancy — NEET Biology
📚 Practice ConceptHave you ever wondered why an elephant always gives birth only to a baby elephant and not some other animal? Or why a mango seed forms only a mango plant and not any other plant?
Which of the following statements regarding the characteristics of polygenic inheritance are NOT correct? S1: Polygenic traits always show distinct alternate forms, unlike Mendelian traits. S2: The expression of polygenic traits is often significantly influenced by environmental factors. S3: The phenotypes of polygenic traits are typically distributed as a bell-shaped curve in a population. S4: Alleles involved in polygenic inheritance often have a cumulative or additive effect on the phenotype. S5: A single gene with multiple phenotypic expressions is an example of polygenic inheritance.
View solution & NCERT explanation
Correct answer: B — S1 and S5 are not correct
The core concept is to identify incorrect statements about polygenic inheritance characteristics. S1: Not Correct. Polygenic traits are not distinct but are spread across a gradient, showing continuous variation. Mendelian traits (monogenic) show distinct alternate forms (e.g., tall or dwarf). S2: Correct. The NCERT states that polygenic inheritance also takes into account the influence of environment. S3: Correct. Traits spread across a gradient (continuous variation) typically result in a bell-shaped curve (normal distribution) when phenotypes are plotted across a population. S4: Correct. The NCERT mentions that in a polygenic trait, the phenotype reflects the contribution of each allele, i.e., the effect of each allele is additive. S5: Not Correct. A single gene exhibiting multiple phenotypic expressions is termed pleiotropy, not polygenic inheritance. Polygenic inheritance involves multiple genes controlling a single trait. Therefore, statements S1 and S5 are not correct.
What does NCERT say about Have you ever wondered?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.