Table 5.

Comparison of Selection Analyses on Pollen and Sporophytic Genes in Arabidopsis thaliana from This and Two Previous Studies

Study	Data Set	Results
Szövényi et al. (2013)	Number of genes in two data sets: 64 and 425 haploid-specific genes, 2,598 and 2,699 diploid-specific genes, 8,806 and 8,246 unspecific genes. Polymorphism data: 19 strains	dN/dS: haploid > diploid > unspecific. pN/pS: haploid > diploid > unspecific
Gossmann et al. (2014)	14,159 pollen genes, 11,657 pollen tube genes, 7,832 sperm cell genes, and 476 random genes.a Polymorphism data: 80 strains	dN/dS: no difference between pollen and random genes. Nucleotide diversity: no difference between pollen and random genes, lower in sperm cell genes. DFE: greater purifying and adaptive selection in pollen genes (excluding sperm cells) than in random genes
Current study	1,552 pollen-specific genes and 5,494 sporophyte-specific genes. Polymorphism data: 80 strains for DFE analysis, otherwise 269	dN/dS: pollen genes > sporophyte genes. πn and θn: pollen genes > sporophyte genes. Stop codons and frameshifts: pollen genes > sporophyte genes. DFE: weaker purifying selection in pollen genes, stronger adaptive selection in sporophyte genes. Positive selection based on divergence data: pollen > sporophyte genes

^aThis study also analyzed genes with expression bias in female tissues.