Navigation Links
Chromosomal crossover

Chromosomal crossover is the process by which two chromosomes, paired up during Prophase I of meiosis, exchange some distal portion of their DNA. Crossover occurs when two chromosomes, normally two homologous instances of the same chromosome, break and then reconnect but to the different end piece. If they break at the same place or locus in the sequence of base pairs, the result is an exchange of genes. This outcome is the normal way for crossover to occur. If they break at slightly different loci, the result can be a duplication of genes on one chromosome and a deletion of these on the other. If they break and rejoin on opposite sides of the centromere, the result can be one chromosome being lost during cell division. If homologous chromosome are not perfectly aligned an unequal crossover may occur, an unequal crossover can create duplicate genes.

Any pair of homologous chromosomes may be expected to cross over three or four times during meiosis. This aids evolution by increasing independent assortment, and reducing the genetic linkage between genes on the same chromosome.

The physical basis of crossing over was first demonstrated by Harriet Creighton and Barbara McClintock in 1931.

See also


(Date:9/10/2015)... -- This report provides detailed descriptions of the sensor ... sensor types that will dominate in the future. Many ... wearable technology hype curve in the last five years ... with all of them is the prominence of sensor ... functions. Sensors collect data about the physical and chemical ...
(Date:9/10/2015)... Report Details The global wearable ... previous expectations of revenues, consumer adoption and even technological ... which wearables begin to achieve that mass market acceptance ... reasons is the entrance of Apple to the SmartWatches ... but the overall size of the wearable technology market. ...
(Date:9/10/2015)... 2015  NXT-ID, Inc. (NASDAQ: NXTD ) ("NXT-ID" ... the growing mobile commerce market, announces that the ... of Modern, will feature the Wocket® smart wallet for ... . Touch Of Modern is an ... products to its 7.2 million members. Customers are affluent, ...
Breaking Biology News(10 mins):
Other biology definition