Meiosis results in independent assortment of egg-derived and sperm-derived chromosomes. If 2𝑛=4 for a given organism, and there is no crossing over, what is the chance that a gamete produced by this diploid organism will receive only sperm-derived chromosomes? In domestic cats, 2𝑛=38. What is the chance that a cat gamete contains only egg-derived chromosomes?

Verified step by step guidance

1. Identify the number of chromosomes in a haploid set for the given organism. Since 2n=4, the haploid number n=2.
2. Understand that each gamete receives one of each chromosome pair, and each chromosome can be either egg-derived or sperm-derived. The total number of combinations of chromosome origins in the gametes is 2^n.
3. Calculate the probability of all chromosomes in a gamete being sperm-derived. Since each chromosome independently has a 1/2 chance of being sperm-derived, the probability for all chromosomes being sperm-derived is (1/2)^n.
4. Apply the same logic to the domestic cat scenario where 2n=38, thus n=19. Calculate the probability of all chromosomes in a cat gamete being egg-derived using the formula (1/2)^n.
5. Interpret the results to understand the rarity of a gamete receiving only sperm-derived or only egg-derived chromosomes, especially as the number of chromosomes increases.

Key Concepts

Meiosis

Meiosis is a specialized type of cell division that reduces the chromosome number by half, resulting in four genetically diverse gametes. It consists of two sequential divisions: meiosis I and meiosis II. During meiosis, homologous chromosomes are separated, and independent assortment occurs, which contributes to genetic variation. This process is crucial for sexual reproduction, as it ensures that offspring receive a mix of genetic material from both parents.

Independent Assortment

Independent assortment is a principle of genetics that describes how different genes independently separate from one another when reproductive cells develop. In meiosis, the orientation of homologous chromosome pairs during metaphase I determines which chromosomes are distributed to gametes. This means that the combination of chromosomes in gametes is random, leading to a variety of genetic combinations in offspring, which is essential for evolution and adaptation.

Gamete Formation and Probability

Gamete formation involves the production of sperm and egg cells through meiosis, where each gamete receives a random assortment of chromosomes. The probability of a gamete containing only chromosomes from one parent can be calculated based on the number of chromosome pairs. For an organism with 2n=4, there are two pairs of chromosomes, leading to a 1 in 4 chance for a gamete to receive only one parent's chromosomes. In domestic cats with 2n=38, the same principle applies, but the calculations involve more chromosome pairs.