Powerful decomposition of complex traits in a diploid model

Area of Science:

• Genetics
• Quantitative Genetics
• Systems Biology

Background:

• Understanding trait variation is crucial in life sciences.
• Previous methods had limitations in fully decomposing genetic causes of traits.

Purpose of the Study:

• Introduce a novel framework for complete decomposition of trait variation in diploid organisms.
• To precisely estimate genetic components contributing to trait differences.

Main Methods:

• Developed Phased Outbred Lines (POLs) by sequencing and pairing recombinant gametes from two natural genomes.
• Created an array of diploid hybrids with fully assembled and phased genomes.
• Partitioned fitness traits in 6,642 Saccharomyces cerevisiae POLs across diverse environments.

Main Results:

• Achieved near-complete trait heritability.
• Precisely estimated additive (73%), dominance (10%), second-order (7%), and third-order (1.7%) epistasis components.
• Mapped quantitative trait loci (QTLs), finding nonadditive QTLs outnumbered additive loci (3:1) and dominant contributions to heterosis exceeded overdominant ones.

Conclusions:

• The Phased Outbred Lines (POLs) framework provides the most complete decomposition of diploid traits to date.
• The approach is adaptable to most model organisms for dissecting genetic architecture.
• Revealed extensive pleiotropy and the significant role of nonadditive genetic effects in trait variation.