heritability
Ayroles JF, Carbone MA, Stone EA, Jordan KW, Lyman RF, Magwire MM, Rollmann SM, Duncan LH, Lawrence F, Anholt RR & Mackay TF 2009 Systems genetics of complex traits in Drosophila melanogaster. Nat Genet 41:299-307.
- we observed 10,096 genetically variable transcripts and high heritabilities for all organismal phenotypes
- the bulk of genetic variation for complex traits may be due to alleles with small and possibly context-dependent effects
- this 'systems genetics' approach will yield a detailed map of genetic variants associated with each organismal phenotype in each environment, provide a functional context for interpreting the phenotypes, elucidate the genetic underpinnings that govern the interdependence of multiple phenotypes, and address the long-standing question of the genetic basis of genotype by environment interaction
- we used analysis of variance (ANOVA) to partition variation in expression between sexes, among lines, and the sex × line interaction for each expressed transcript
- a significant sex × line interaction indicates genetic variation in the magnitude of the sex dimorphism among the lines
- there is a significant positive correlation between heritability of transcript abundance and ω, the ratio of nonsynonymous to synonymous substitutions, among single-copy genes with orthologs in six melanogaster group species
- genes encoding transcripts with lower heritabilities experience stronger purifying selection than do genes encoding transcripts with high heritabilities
- high heritabilities are expected for genes under mutation-drift equilibrium
- it is not likely that this mechanism accounts for the observed high heritabilities of transcript abundance
- the estimates of ω for these loci are much less than the neutral expectation of unity
- the high heritabilities for these transcripts could be the result of more complex evolutionary dynamics
