General cognitive ability (g) is a general mental ability to reason, solve problems, comprehend complex ideas, think abstractly, learn quickly and learn from experience. Currently used IQ tests are excellent predictors of g. Heritability estimates for g range between 0.30 and 0.75 making it one of the most heritable human behavioural traits. Many behavioural phenotypes, including g, can be described as complex traits. Inheritance of such traits is governed by a mixture of genetic and environmental factors. Genetic factors contributing to total variance in g are likely to be numerous and additive in nature. In order to identify some of the genetic loci contributing to the total variance in g two approaches were employed. First, a genome-wide association study and second, candidate gene study. Genome-wide association study involved testing 1847 microsatellite markers with an average spacing of 2cM. Markers were initially screened on "original" DNA samples. This was followed by testing all positive findings on an independent "replication" sample set. Only one marker, D4S2460, was significant when all the stages of the study were completed. Investigation of candidate genes involved testing of known Apolipoprotein E (ApoE) promoter polymorphisms and Calcium/calmodulin dependant protein kinase II alpha (CaMKII-a) polymorphisms identified in our laboratories through mutation detection techniques. None of the polymorphisms in either of the two genes showed statistically significant association with a general cognitive ability.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:583637 |
| Date | January 2005 |
| Creators | Turic, Dragana |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/55617/ |
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