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Apr 27, 2017 · Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis, which results in new allelic combinations in the daughter cells. Learn how crossing over occurs, what are its functions, and how it affects linkage maps and inheritance patterns.
Crossing over is important for the normal segregation of chromosomes during meiosis. Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the centromere are no longer identical.
4 days ago · Crossing over is a cellular process that happens during meiosis when chromosomes of the same type are lined up. When two chromosomes — one from the mother and one from the father — line up, parts of the chromosome can be switched.
Learn how meiosis reduces chromosome number by half and produces gametes with new combinations of genes. Crossing over is the exchange of DNA between homologous chromosomes that occurs during prophase I of meiosis.
- Good question! I think that is assumed to be generally true, but it would be very hard to test in most organisms. The only evidence for this being...
- there was no chromosomal duplication in meiosis II only the centrosome duplicated. If there would have been chromosomal duplication cells would nev...
- Well, it works based on patterns of nuclear defragmentation. On the places where old fragments of a nucleus are, new form. Also, thanks to cytokine...
- The number of chromosomes becomes haploid in meiosis I, because the actual sister chromatids are not pulled apart by spindle fibers. For example, i...
- Remember that when replicating in interphase, the chromosome number DOES NOT CHANGE in interphase before S (replication phase) we have 46 single st...
- Interphase _is_ stage of the cell cycle, but _not_ a stage of _cell division_ (meisosis). Interphase is that gap phase (exactly G0) where cell cycl...
- Yes, meiosis's goal is to make a zygote. This zygote will (hopefully) turn into an embryo, then a fetus, which eventually becomes a human if everyt...
- You're almost correct. Males transfer sperm to the female and only one of the many sperm ends up fertilizing the egg. Then the fertilized egg becom...
- Correct. Meisosi II is reduction division. Why? Because, final products of meiosis, *gametes* are _haploid cells_. Just remember that ova and sperm...
- 1. Chromosomes condense and homologs loosely pair along their lengths, aligned by gene. 2. The paired homologs become physically connected along th...
Crossing over is the exchange of genetic material between homologous chromosomes during meiosis I. It increases genetic diversity and helps in genetic mapping of genes on chromosomes.
Crossing over leads to re-combinations or new combinations between linked genes. Crossing over generally yields two recombinant types or crossover types and two parental types or non-crossover types. 6. Crossing over generally leads to exchange of equal segments or genes and recombination is always reciprocal.
Learn how chromosomal crossover increases genetic variation in gametes and offspring during meiosis I. Watch a video and read comments from other learners and experts.
- 12 min
- Sal Khan
