the separation of homologous chromosomes during meiosis is called homoplasmy.
the separation of homologous chromosomes during meiosis is called homoplasmy.
the separation of homologous chromosomes during meiosis is called?
homoplasmy
in meiosis, dna replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. the two meiotic divisions are known as meiosis i and meiosis ii. before meiosis begins, during s phase of the cell cycle, the dna of each chromosome is replicated so that it consists of two identical sister chromatids, which remain held together through sister chromatid cohesion. this s-phase can be referred to as "premeiotic s-phase" or "meiotic s-phase". immediately following dna replication, meiotic cells enter a prolonged g2-like stage known as meiotic prophase. during this time, homologous chromosomes pair with each other and undergo genetic recombination, a programmed process in which dna is cut and then repaired, which allows them to exchange some of their genetic information. a subset of recombination events results in crossovers, which create physical links known as chiasmata (singular: chiasma, for the greek letter chi (x)) between the homologous chromosomes. in most organisms, these links are essential to direct each pair of homologous chromosomes to segregate away from each other during meiosis i, resulting in two haploid cells that have half the number of chromosomes as the parent cell. during meiosis ii, the cohesion between sister chromatids is released and they segregate from one another, as during mitosis. in some cases all four of the meiotic products form gametes such as sperm, spores, or pollen. in female animals, three of the four meiotic products are typically eliminated by extrusion into polar bodies, and only one cell develops to
meiosis
prophase i is typically the longest phase of meiosis. during prophase i, homologous chromosomes pair and exchange dna (homologous recombination). this often results in chromosomal crossover. this process is critical for pairing between homologous chromosomes and hence for accurate segregation of the chromosomes at the first meiosis division. the new combinations of dna created during crossover are a significant source of genetic variation, and result in new combinations of alleles, which may be beneficial. the paired and replicated chromosomes are called bivalents or tetrads, which have two chromosomes and four chromatids, with one chromosome coming from each parent. the process of pairing the homologous chromosomes is called synapsis. at this stage, non-sister chromatids may cross-over at points called chiasmata (plural; singular chiasma). prophase i has historically been divided into a series of substages which are named according to the appearance of chromosomes.
meiosis