RNAProtein160-page16 - This results in part of the DNA...

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Gene Expression – DNA to Protein - 16 Deletion Duplication A common duplication, the trinucleotide repeat, occurs within some abnormal genes, and is responsible for several genetic disorders, including fragile X syndrome and Huntington's disease. Gene Transfers We have discussed how recombination between homologous chromosomes changes the specific alleles on a given chromosome and adds to the variations seen in populations. Recombination can also involve gene transfer. Gene transfer is when genes from one chromosome (or even organism) are transferred to a different chromosome or rearranged within a chromosome. There are two common gene transfers: inversions and translocations (or transpositions). Changing Gene Positions – Chromosome Structural Change Gene Inversions For an inversion, a group of genes can have their order reversed in the chromosome so that a gene sequence that should be A-B-C-D-E-F-G-H is changed to A-B-F-E-D-C-G-H instead.
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Unformatted text preview: This results in part of the DNA being "backwards" and unreadable. Many gametes are not viable after inversions. Gene Translocation A gene can be transposed or translocated (moved) to a different location along the gene, so that the sequence might read A-B-C-E-F-G-D rather than A-B-C-D-E-F-G. Since many genes are read in sequence, altering the sequence may affect the ability to read a gene. Translocation can also involved transferring a part of a chromosome to a different, non-homologous chromosome. Reciprocal translocations involve exchange of genes between non-homologous chromosomes. The translocation of a piece of the human #22 chromosome to the #9 chromosome causes a form of leukemia because it interferes with a gene that controls cell division. This abnormal chromosome is called the Philadelphia chromosome, from the city in which the researchers who discovered this abnormality lived....
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