Question

Given below are two statements:
Statement (I): An exception to Mendel's law is linkage.
Statement (II): Many traits are inherited in a non-Mendelian fashion.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Mendel's choice of traits in pea plants was fortunate, as the genes controlling them were located on different chromosomes or far enough apart to behave as if they were, allowing him to observe independent assortment.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Mendelian genetics describes the inheritance of traits controlled by single genes with dominant and recessive alleles that segregate and assort independently.
Several genetic phenomena deviate from these rules, representing non-Mendelian patterns of inheritance.
Detailed Explanation:
Let us analyze both statements:
Statement (I) states that linkage is an exception to Mendel's laws.
Mendel's Law of Independent Assortment states that alleles of different genes segregate independently of one another during gamete formation.
This rule applies only when genes are located on different chromosomes or are located far apart on the same chromosome.
When genes are located close to each other on the same chromosome, they are "linked" and tend to be inherited together during meiosis, unless separated by crossing over.
Thus, linkage is a well-known exception to Mendel's law of independent assortment.
This makes Statement (I) correct.
Statement (II) states that many traits are inherited in a non-Mendelian fashion.
Many complex, quantitative traits in animals (such as milk production, growth rate, and disease resistance) are polygenic, meaning they are controlled by multiple genes interacting with each other and the environment.
Other non-Mendelian inheritance patterns include incomplete dominance, co-dominance, multiple alleles, epistasis, and mitochondrial (extranuclear) inheritance.
This makes Statement (II) correct.

Step 2: Final Answer:
Both Statement (I) and Statement (II) are correct.