Chromosomal Crossover

Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis (pachytene) in a process called synapsis. Synapsis begins before the synaptonemal complex develops, and is not completed until near the end of prophase I. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome.

Crossing over was described, in theory, by Thomas Hunt Morgan. He relied on the discovery of the Belgian Professor Frans Alfons Janssens of the University of Leuven who described the phenomenon in 1909 and had called it 'chiasmatypie'. The term chiasma is linked if not identical to chromosomal crossover. Morgan immediately saw the great importance of Janssens' cytological interpretation of chiasmata to the experimental results of his research on the heredity of Drosophila. The physical basis of crossing over was first demonstrated by Harriet Creighton and Barbara McClintock in 1931.

Read more about Chromosomal CrossoverChemistry, Consequences, Problems

Other articles related to "chromosomal crossover, crossover, crossovers":

Genetic Recombination - Chromosomal Crossover
... recombination also occurs in meiosis, where it facilitates chromosomal crossover ... The crossover process leads to offspring's having different combinations of genes from those of their parents, and can occasionally produce new chimeric ... Chromosomal crossover refers to recombination between the paired chromosomes inherited from each of one's parents, generally occurring during meiosis ...
Deoxyribonucleic Acid - Genetic Recombination
... of the few times chromosomes interact is during chromosomal crossover when they recombine ... Chromosomal crossover is when two DNA helices break, swap a section and then rejoin ... The most common form of chromosomal crossover is homologous recombination, where the two chromosomes involved share very similar sequences ...
Homologous Recombination - In Eukaryotes - Models - DSBR Pathway
... The DSBR pathway commonly results in crossover, though it can sometimes result in non-crossover products the ability of a broken DNA molecule to collect sequences from ... Because of this tendency for chromosomal crossover, the DSBR pathway is a likely model of how homologous recombination occurs during meiosis ... Whether recombination in the DSBR pathway results in chromosomal crossover is determined by how the double Holliday junction is cut, or "resolved" ...
Chromosomal Crossover - Problems
... Although crossovers typically occur between homologous regions of matching chromosomes, similarities in sequence can result in mismatched alignments ...
Genetics - Molecular Basis For Inheritance - Recombination and Linkage
... never recombine, however, were it not for the process of chromosomal crossover ... During crossover, chromosomes exchange stretches of DNA, effectively shuffling the gene alleles between the chromosomes ... This process of chromosomal crossover generally occurs during meiosis, a series of cell divisions that creates haploid cells ...