Understanding Mendel's Law of Segregation
Mendel's first law, the Law of Segregation, describes how paired hereditary elements (genes) separate during the formation of reproductive cells (gametes).
Segregation of Alleles
During gamete formation (meiosis), the two alleles for each gene present in a diploid organism separate from each other so that each gamete receives only one allele.
- For example, if a gene has alleles 'A' and 'a', a parent with genotype 'Aa' will produce gametes, half carrying 'A' and half carrying 'a'.
Applying the Law
The question asks what segregates during gamete formation according to Mendel's law of segregation. Based on the law:
- Alleles of a gene separate during meiosis.
Analyzing Incorrect Options
- Mitochondrial genes are inherited maternally and do not follow the segregation pattern of nuclear genes described by Mendel's laws.
- Linked genes (on the same chromosome) tend to be inherited together, violating the principle of segregation unless crossing over occurs. The law specifically addresses the separation of different versions (alleles) of the *same* gene.
- Unlinked genes assort independently (Mendel's second law), which is a different process than segregation.
Therefore, the segregation described by Mendel's law applies specifically to the separation of alleles of a gene.
Important Questions from Mendelian Inheritance
- Fabry disease in humans is a X-linked disease. The probability (in percentage) for a phenotypically normal father and a carrier mother to have a son with Fabry disease is ________.
The allele associated with albinism in humans is recessive ($c$). The probability that an albino male ($cc$) and a carrier female ($Cc$) will have an offspring with normal skin pigmentation is _________.
(Round off to one decimal place)
- The blood group of the mother is A⁺ and that of the father is AB⁺. Which of the following statements is/are correct?
- Assuming independent assortment and no recombination, the number of different combinations of maternal and paternal chromosomes in gametes of an organism with a diploid number of 12 is ________.
In a Mendel's dihybrid experiment, a homozygous pea plant with round yellow seeds was crossed with a homozygous plant with wrinkled green seeds.
F₁ intercross produced 560 F₂ progeny. The number of F₂ progeny having both dominant traits (round and yellow) is ________
