Molecular Genetics and Psychology.pdf

Molecular Genetics and Psychology 30 October 2023 14:56 Main Ideas SNPs Genome-wide association Polygenic scores Psychological applications Notes Notes Quantitative Genetics vs Molecular Genetics ○ Quantitative genetics focuses on the scientific examination of phenotypes that vary continuously ○ Mol...

Molecular Genetics and Psychology 30 October 2023 14:56 Main Ideas SNPs Genome-wide association Polygenic scores Psychological applications Notes Notes Quantitative Genetics vs Molecular Genetics ○ Quantitative genetics focuses on the scientific examination of phenotypes that vary continuously ○ Molecular genetics examines the genes at the molecular levels Molecular Genetics Timeline Creating polygenic scores Can create a scale from questionnaire items For each individual = composite score of SNPs weighted by their association with a trait Example of polygenic scores available for psychological traits Molecular Genomics Timeline ○ Studying DNA ○ Acquire the DNA through saliva collection kits or extraction techniques ○ Genotype single-nucleotide polymorphisms (SNPs) ○ Correlate SNPs with traits (association) Genotyping SNPs ○ Using fluorescent markers to tag bases in DNA (A -C-G-T) ○ Can identify exons (codes for proteins) and introns Finding SNPs associated with complex traits and common disorders ○ A correlation in the population between an allele and a quantitative trait or common disorder ○ Most common designs: ▪ Cases versus controls □ - e.g., schizophrenics versus non-schizophrenics □ Unselected sample: Correlate genotypes with quantitative traits What is unique about polygenic scores? 100% reliable Unbiased (not affected by training, faking or anxiety) One-time cost Predict from birth Practical reasons for using polygenic scores across the behavioural sciences Can be used in any sample of unrelated individuals Need large samples for GWAS, but don’t need large samples to use polygenic scores Research application Psychology research Clinical psychology/psychiatry Understanding ourselves Multivariate Developmental GE interplay Before and after of approach clinical diagnoses Genome-wide association timeline 1990s --> candidate gene association 1990s-2000s --> genome-wide association 2000s --> GeneChip 2000s-2010s --> WTCCC GWAS GWA Many DNA variants contribute to heritability Larger samples needed to detect small effects Synthesising disciplines in Genetics Summary PSYC0036 Genes and Behaviour Page 1 ○ Now can usefully apply polygenic scores PSYC0036 Genes and Behaviour Page 2