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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.
Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes' non-sister chromatids that results in recombinant chromosomes.
Feb 26, 2009 · Crossing Over: Directed by Wayne Kramer. With Harrison Ford, Ray Liotta, Ashley Judd, Jim Sturgess. Crossing Over is about illegal aliens of many nationalities in the Los Angeles area and the authorities and individuals dealing with them.
- (25K)
- Crime, Drama
- Wayne Kramer
- 2009-02-26
Learn how chromosomal crossover increases genetic variation in gametes and offspring during prophase I of meiosis. Watch a video and read comments from other learners and experts.
- 12 min
- Sal Khan
- *Tetrad* or *bivalents* form when duplicated chromosomes, each composed of two identical chromatids, pair up and complete the process of crossing o...
- Great question! This is still being actively studied, but it does seem to depend (at least in part) on comparing the sequences of the chromosomes....
- Meiosis scrambles the genetic information from the individuals parents. So, a "maternal" chromosome means a chromosome that the individual producin...
- When the chromosomes duplicate during interphase the genetic material is doubled but it is still considered to have the same number of chromosomes...
- No. Crossover INCREASES genetic variation in gametes and offspring. Crossover allows the chromosomes you pass to your children to have some genes f...
- Every first meiotic division (when prophase I happen).
- The short chromosome can overlap too, it's just that he used an example of how crossing over can occur.
- The change in eye color would likely be explained by a change in epigenetics, how your cells read and express your genes. It is unlikely (though po...
- Exactly. That's why you and your siblings are so different. :) Why they are not inherited in pairs? Because it would create tetrads. If tetrads do...
Crossing over. The points where homologues cross over and exchange genetic material are chosen more or less at random, and they will be different in each cell that goes through meiosis. If meiosis happens many times, as in humans, crossovers will happen at many different points.
- 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...
1 day 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.
Describe how crossing-over, independent assortment, and random fertilization lead to genetic variation. How many combinations of chromosomes are possible from sexual reproduction in humans? Create a diagram to show how crossing-over occurs and how it creates new gene combinations on each chromosome.
