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"Chromosome 1 from your dad has to be paired with chromosome 1 from your mom, chromosome 2 from your dad with chromosome 2 from your mom, and so on," Hawley explains, "and that's a real...
- Reproduction
Reproduction is the biological process by which new...
- Current Biology
Current Biology is a scientific journal that covers all...
- Meiosis
Each of your cells contains two copies of 23 chromosomes,...
- Reproduction
Dec 15, 2022 · The two chromosomes in each cell that are homologous and have the same genes (but perhaps different alleles if the organism is heterozygous) will pair closely. This close association, or synapsis, allows the homologous chromosomes to crossover and exchange identical parts.
In reality, crossing-over between chromatids during prophase I of meiosis mixes up pieces of chromosomes between homologue pairs, a phenomenon called recombination.
During meiosis in humans, 1 diploid cell (with 46 chromosomes or 23 pairs) undergoes 2 cycles of cell division but only 1 round of DNA replication. The result is 4 haploid daughter cells known as gametes or egg and sperm cells (each with 23 chromosomes – 1 from each pair in the diploid cell).
The homologous pairs orient themselves randomly at the equator. For example, if the two homologous members of chromosome 1 are labeled a and b, then the chromosomes could line up a-b, or b-a. This is important in determining the genes carried by a gamete, as each will only receive one of the two homologous chromosomes.
Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate.
People also ask
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How does meiosis create variation? In terms of the actual, cellular processes, two things occur: As meiosis reduces chromosome number from diploid (two sets) to haploid (one set), a cellular “choice” has to be made. The choice is this: for each homologous pair, which chromosome (maternal or paternal) will be sent to the haploid gamete?
