Table 1.
Common factor solutions for the genetic (top section) and phenotypic (bottom section) covariance structure of seven UKB cognitive traits.
| Standardized Factor Loadings | Common (g) and specific (s) sources of genetic variation | ||||||
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| Genetic g | Proportion of genetic variation explained by genetic g and genetic s | Proportion of phenotypic variation explained by genetic g and genetic s (HapMap3 Common Variants Only) | |||||
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| Cognitive Trait | Estimate | SE | Common (g) | Specific (s) | Common (g) | Specific (s) | Total SNP h2 |
| Matrices | 0.826 | 0.070 | 68.23% | 31.77% | 10.60% | 4.90% | 15.50% |
| Memory | 0.651 | 0.031 | 42.38% | 57.62% | 1.70% | 2.30% | 4.00% |
| RT | 0.308 | 0.026 | 9.49% | 90.51% | 0.70% | 6.70% | 7.40% |
| Symbol | 0.831 | 0.034 | 7.60% | 3.40% | 11.00% | ||
| Digit | 69.06% | 30.94% | |||||
| Trails-B | 0.976 | 0.035 | 95.26% | 4.74% | 14.20% | 0.70% | 14.90% |
| Tower | 0.853 | 0.080 | 72.76% | 27.24% | 8.30% | 3.10% | 11.40% |
| VNR | 0.717 | 0.024 | 51.41% | 48.59% | 10.90% | 10.30% | 21.20% |
| Mean % | 58.36% | 41.64% | 7.71% | 4.49% | 12.20% | ||
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| Phenotypic g | Proportion of phenotypic variation explained by phenotypic g and phenotypic s | ||||||
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| Cognitive Trait | Estimate | SE | Common (g) | Specific (s) | |||
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| Matrices | 0.501 | 0.009 | 25.10% | 74.90% | |||
| Memory | 0.257 | 0.003 | 6.60% | 93.40% | |||
| RT | 0.231 | 0.003 | 5.34% | 94.66% | |||
| Symbol Digit | 0.628 | 0.004 | 39.44% | 60.56% | |||
| Trails-B | 0.766 | 0.003 | 58.68% | 41.32% | |||
| Tower | 0.487 | 0.009 | 23.72% | 76.28% | |||
| VNR | 0.514 | 0.003 | 26.42% | 73.58% | |||
| Mean % | 26.50% | 73.50% | |||||
Note. Matrices = Matrix Pattern Completion task; Memory = Memory – Pairs Matching Test; RT = Reaction Time; Symbol Digit = Symbol Digit Substitution Task; Trails-B = Trail Making Test - B; Tower = Tower Rearranging Task; VNR = Verbal Numerical Reasoning Test. All traits are scaled such that higher scores indicate higher cognitive performance. Total SNP h2 = total proportion of phenotypic variance in the corresponding cognitive trait accounted for by all tagged common variants. By definition, the common (g) and specific (s) proportional contributions to total phenotypic variation sum to the total SNP h2, and the common (g) and specific (s) proportional contributions to genetic variation sum to 100%. Note: Standardized factor loadings indicate the standardized linear relationship between the factor and each of the cognitive outcomes. Models are fit to LDSC-derived genetic covariance matrices using Genomics SEM. As per best practices for LDSC, genetic covariance matrices were derived using HapMap3 SNPs with minor allele frequencies > 1%, excluding SNPs with INFO < 0.9 and those from the MHC region.