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8 gru 2016 · Fruit flies have 4 pairs of chromosomes or 8 chromosomes in regular cells. Before meiosis takes place, each chromosome is replicated, leaving 8 chromosomes and 16 sister chromatids. Meiosis I takes place, and there are 2 cells, each with only 4 chromosomes.
Then, while the homologous chromosomes are tightly paired, the members of each pair trade adjacent bits of DNA in a process called crossing over, also known as recombination (Figure 1). This ...
21 paź 2023 · In biology, meiosis is the process where a cell replicates DNA once but divides twice, producing four cells that have half the genetic information of the original cell. It is how organisms produce gametes or sex cells, which are eggs in females and sperm in males. In meiosis one cell divides twice, forming four cells.
Explain the differences between meiosis and mitosis. Explain the mechanisms within the meiotic process that produce genetic variation among the haploid gametes. Sexual reproduction requires the union of two specialized cells, called gametes, each of which contains one set of chromosomes.
31 paź 2023 · The total possible number of different gametes is 2n, where n equals the number of chromosomes in a set. In this example, there are four possible genetic combinations for the gametes. With n = 23 in human cells, there are over 8 million possible combinations of paternal and maternal chromosomes.
In meiosis I, the homologous chromosome pairs become associated with each other, are bound together with the synaptonemal complex, develop chiasmata and undergo crossover between sister chromatids, and line up along the metaphase plate in tetrads with kinetochore fibers from opposite spindle poles attached to each kinetochore of a homolog in a ...
Genetic variation occurs during meiosis I, in which homologous chromosomes pair and exchange non-sister chromatid segments (crossover). Here the homologous chromosomes separate into different nuclei, causing a reduction in “ploidy.”
