Genes homologous recombination

De Lozanne, A. Spudich, J.A. (1987). Disruption of the Dictyostelium myosin heavy chain gene by homologous recombination. Science 236, 1086-1091. 

Gene knockouts were performed by homologous recombination in mice. The enzymes are characterized as neuronal, inducible (macrophage), and endothelial because these were the sites in which they were first identified. However, all three enzymes have been found in other sites, and the neuronal enzyme is also inducible. Each gene has been cloned, and its chromosomal location in humans has been determined. 

Homologous Two DNA sequences that are very similar or identical. Homologous recombination occurs between two genes that have very similar or identical sequences. Nonhomologous Two DNA sequences that are very different. Nonhomologous recombination can occur between two unrelated genes. 

ALIGNED, HOMOLOGOUS RECOMBINATION swaps information between the same genes on two copies of the same chromosome. Genes are not lost or duplicated, nor is their order changed. Different combination of specific alleles (copies of same gene) does occur. 

Inactivation of the a-synuclein gene by homologous recombination results in mice that appear largely normal [3]. Analysis of mice lacking y-synuclein has similarly failed to reveal any gross abnormalities [4]. In hippocampal slices from mice without a-synuclein, the replenishment of docked vesicles by reserve pool vesicles was slower than in slices from control mice. It suggests a physiological role for a-synuclein in the mobilization of synaptic vesicles. 

Inactivation of the tau gene by homologous recombination results in mice that are largely normal [22], indicating that tau is a nonessential protein. This may reflect functional redundancy. Thus, mice doubly deficient in tau and the microtubule-associated protein MAP IB exhibit nervous system defects that are more severe than those in the MAP IB single knockout line. 

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