Search results
Results from the WOW.Com Content Network
The two pathways for homologous recombination in eukaryotes, showing the formation and resolution of Holliday junctions. The Holliday junction is a key intermediate in homologous recombination, a biological process that increases genetic diversity by shifting genes between two chromosomes, as well as site-specific recombination events involving integrases.
The NCO/SDSA pathway contributes little to genetic variation, since the arms of the chromosomes flanking the recombination event remain in the parental configuration. Thus, explanations for the adaptive function of meiosis that focus exclusively on crossing-over are inadequate to explain the majority of recombination events.
During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in which a length of DNA on one chromatid is swapped with a length of DNA on the corresponding homologous non-sister chromatid. This can result in reassortment of otherwise linked alleles.
Gene conversion is the process by which one DNA sequence replaces a homologous sequence such that the sequences become identical after the conversion. [1] Gene conversion can be either allelic, meaning that one allele of the same gene replaces another allele, or ectopic, meaning that one paralogous DNA sequence converts another.
There are two distinctive mapping approaches used in the field of genome mapping: genetic maps (also known as linkage maps) [7] and physical maps. [3] While both maps are a collection of genetic markers and gene loci, [8] genetic maps' distances are based on the genetic linkage information, while physical maps use actual physical distances usually measured in number of base pairs.
Transformation has a different meaning in relation to animals, indicating progression to a cancerous state, so the process used to insert foreign DNA into animal cells is usually called transfection. [35] There are many ways to directly introduce DNA into animal cells in vitro. Often these cells are stem cells that are used for gene therapy.
The meiotic checkpoint network is a DNA damage response system that controls double strand break repair, chromatin structure, and the movement and pairing of chromosomes. [17] The system consists of multiple pathways (including the meiotic recombination checkpoint ) that prevent the cell from entering metaphase I with errors due to recombination.
DNA transposons are DNA sequences, sometimes referred to "jumping genes", that can move and integrate to different locations within the genome. [1] They are class II transposable elements (TEs) that move through a DNA intermediate, as opposed to class I TEs, retrotransposons , that move through an RNA intermediate. [ 2 ]