X marks the spot.X marks the spot X Marks the Spot is a quiz and panel game that has been broadcast on BBC Radio 4 since 1998 which could be likened to be a more light-hearted version of Round Britain Quiz. It was presented by the comedian and author Pete McCarthy until his death in October 2004. Evidence is mounting that, in some cases of manic depression,there is a gene near one tip of the X chromosome X chromosome One of the two sex chromosomes (the other is Y) that determine a person's gender. Normal males have both an X and a Y chromosome, and normal females have two X chromosomes. that predisposes its bearers to the disorder. Scientists who recently studied five families in Jerusalem used DNA-cutting enzymes to locate two genetic markers--one for color blindness color blindness, visual defect resulting in the inability to distinguish colors. About 8% of men and 0.5% of women experience some difficulty in color perception. , the other for a chemical deficiency that causes anemia--at the end of the long arm of the X chromosome. The markers occurred overwhelmingly among subjects with manic depression or related mood disorders (SN: 3/28/87, p.199). Julien Mendlewicz of the Free University of Brussels The Free University of Brussels may refer to one of two Belgian universities, both located in Brussels, Belgium:
DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. was isolated from 89 individuals, 41 of whom had manic depression or severe depression, in 10 families. A genetic marker genetic marker n. A gene phenotypically associated with a particular, easily identified trait and used to identify an individual or cell carrying that gene. for a blood coagulation factor located near the color blindness and anemia markers occurred mainly among family members with the psychiatric diagnoses. The genetic link was emphasized by the fact that no fathersand sons shared mood disorders, say the researchers. The 23rd pair of human chromosomes consists of two X chromosomes for females and one X and one Y chromosome for males. The Y chromosome is inherited from the father. There is probably more than one gene involved in predisposingpeople in different populations to manic depression, note the scientists in the May 30 LANCET. For instance, there is a genetic marker on chromosome 11 linked to manic depression among the Amish (SN: 2/28/87, p.132). But the investigators suggest that the long arm of the X chromosome may hold special promise for tracking down a predisposing gene. "Banking of DNA samples from high-risk persons may lead tothe isolation and sequencing of the [X-chromosome] gene responsible for manic-depressive illness,' they say. |
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