* Before Meiosis (Diploid Cell): A diploid cell has two alleles for each gene, one inherited from each parent.
* Meiosis I (Prophase I - Telophase I):
* Early Stages: Each chromosome duplicates, so there are now two copies of each allele per chromosome.
* Late Stages: Homologous chromosomes (carrying the same genes) pair up and exchange genetic material (crossing over). This doesn't change the total number of alleles, but it creates new combinations of alleles on each chromosome.
* Meiosis II (Prophase II - Telophase II):
* Throughout Meiosis II: The number of alleles per gene remains the same as at the end of Meiosis I. The sister chromatids (identical copies of each chromosome) are separated, so each daughter cell receives one allele for each gene.
Key Points:
* Allele: A specific version of a gene.
* Gene: A segment of DNA that codes for a particular trait.
* Diploid: Having two sets of chromosomes (one from each parent).
* Haploid: Having one set of chromosomes.
Summary:
* Diploid cell (before meiosis): 2 alleles per gene
* End of Meiosis I: 2 alleles per gene (on each chromosome)
* End of Meiosis II: 1 allele per gene (in each haploid daughter cell)
