crossing overthe exchange of
genetic material between members of a
homologous chromosome pair
Source: Jenkins, John B. 1990.
Human Genetics, 2nd Edition. New York: Harper & Row ...
Full article >>>Crossing Over and
Genetic Recombination in
MeiosisCrossing over occurs between equivalent portions of two non
sister chromatids.
Link to an illustrated discussion of
crossing over examined at the level of a
cell undergoing
meiosis.
Full article >>>Crossing over is more likely to occur between genes that are far apart. The farther apart genes are, the greater the
probability that
crossing over will occur between them.
In the example above, we had 8%
crossing over.
Full article >>>Crossing overMain article: Chromosomal
crossoverCrossing over of two
chromosomes occurs during
meiosis. After chromosomal
replication, the four available
chromatids are in tight formation with one another.
Full article >>>Crossing overMain article: Chromosomal
crossoverCrossing over of one of the
chromosomes inherited from each of one's parents occurs during
meiosis in that parent.
Full article >>>crossing over: Where a section of one
chromosome switches places with the same section from the other
chromosome of the pair. This sometimes occurs when a germ
cell makes copies of its
chromosomes before dividing.
Full article >>>crossing over: a process during
prophase I in which
segments of
DNA from one
chromatid in the
tetrad pass to another
chromatid in the
tetrad.
cyanobacteria: see
blue-green algae.
Full article >>>crossing over the reciprocal exchange of
genetic material between non-
sister chromatids during
synapsis of
meiosis I.
Crustaceaclass in the
phylum Arthropoda. Most members of this
class are aquatic, although a few are terrestrial.
Full article >>>crossing overThe reciprocal exchange of
genetic material between non
sister chromatids during
synapsis of
meiosis I.
cryptic coloration ...
Full article >>>Crossing over: The breaking during
meiosis of one maternal and one paternal
chromosome, the exchange of corresponding sections of
DNA, and the rejoining of the
chromosomes. This process can result in an exchange of
alleles between
chromosomes.
Full article >>>Related Terms:
Crossing overThe term coined by M
organ and Cattell (1912) for the occurrence of new combinations of linked
characters.
Full article >>>The exchange of
DNA fragments between two
DNA molecules or
chromatids of paired
chromosomes (during
crossing over) at the
site of identical
nucleotide sequences.
Homozygote.
Full article >>>Animation of
meiosis illustrates the
integration of
replication,
crossing over and
segregation. A series of diagrams assists in understanding
meiosis.
Photomicrographs and drawings of
mitosis are also helpful.
Full article >>>May-Thurner syndrome is compression of the left iliac vein by the artery
crossing over it. This is normal
anatomy, but in some people the artery presses on the vein enough to thicken the vein wall over time.
Full article >>>Events of
Prophase I (save for
synapsis and
crossing over) are similar to those in
Prophase of
mitosis:
chromatin condenses into
chromosomes, the
nucleolus dissolves,
nuclear membrane is disassembled, and the spindle apparatus forms.
Full article >>>An X-shaped
crossing formed by the
crossing over of
homologous chromosomes during
meiosis when
genetic material is exchanged.
Full article >>>But having invented SRY the key driver of the
evolution of the
sex chromosomes was the shutting down of
recombination of
crossing over between this pair.
Full article >>>Recombination frequency. The frequency at which
crossing over occurs between two chromosomal
loci--the
probability that two
loci will become
unlinked during
meiosis.
Full article >>>The exchange of pieces of
DNA during the formation of eggs and
sperm.
Recombination allows the
chromosomes to shuffle their
genetic material, increasing the potential of
genetic diversity.
Homologous recombination is also known as
crossing over.
Full article >>>where pairs of homologous
chromatids remain in contact during late
prophase to
anaphase of the first meiotic
division. The
chiasma indicates where an exchange of homologous
segments has taken place between non
sister chromatids by
crossing over.
Full article >>>This process is the molecular basis of
crossing over during
meiosis and some
DNA repair mechanisms. Another form of
recombination,
site-specific recombination, is found where
transfer, rearrangement or
insertion of specific sections of
DNA occurs e.
Full article >>>'"/>