Mendel’s law of independent assortment states that
A) chromosomes sort independently of each other during mitosis and meiosis.
B) independent sorting of genes produces polyploid plants under some circumstances.
C) each pair of alleles (chromosomes) segregates independently of the other pairs of alleles during gamete formation.
D) genes are sorted concurrently during gamete formation.
The correct answer and explanation is :
Correct Answer: C) each pair of alleles (chromosomes) segregates independently of the other pairs of alleles during gamete formation.
Explanation (Approx. 300 words):
Mendel’s Law of Independent Assortment is one of the foundational principles of classical genetics, first formulated by Gregor Mendel in the mid-1800s through his experiments with pea plants. This law states that alleles of different genes assort independently of one another during the formation of gametes. In other words, the inheritance of one trait generally does not affect the inheritance of another, provided the genes controlling these traits are located on different chromosomes or are far apart on the same chromosome.
Mendel derived this principle by studying dihybrid crosses—crosses between plants that differed in two traits, such as seed shape (round vs. wrinkled) and seed color (yellow vs. green). He observed that the alleles for these traits combined in offspring in predictable ratios, suggesting they were inherited independently.
The mechanism behind this principle is found in meiosis, the type of cell division that produces gametes (sperm and egg cells). During Metaphase I of meiosis, homologous chromosomes (each consisting of two sister chromatids) line up at the equator of the cell randomly with respect to other chromosome pairs. This random orientation leads to the independent assortment of maternal and paternal chromosomes into gametes.
It is important to note that the law of independent assortment applies only when genes are located on different chromosomes or are far enough apart on the same chromosome that crossing over occurs frequently. If genes are located close together on the same chromosome (i.e., they are “linked”), they tend to be inherited together, which can violate independent assortment.
Thus, Option C accurately captures Mendel’s law: “each pair of alleles (chromosomes) segregates independently of the other pairs of alleles during gamete formation.” This principle is key to understanding genetic variation in sexually reproducing organisms.