Genomic diversity of selected EV and LC avian species. (a) Percentage distribution of genome sequences in a 100-kb window as a function of heterozygosity (SNPs/1,000 bp) of nine representative avian species from four orders each: EVs (n = 5) and LC (n = 4) species. Species from the same order are denoted in matching colors (solid, EV; dashed, LC). Note the differences among peaks between 0 and 1 on the heterozygosity axis. (b) Box plot of the average heterozygosity of LC (n = 32) and EV (n = 8) species (t test, P <0.01). (c) STR-based genomic diversity. Genome-wide STR alleles are based on lobSTR software  from resequencing reads of the crested ibis (n = 6; randomly selected from eight samples) and the little egret (n = 6). P values from chi-square test for di-, tri-, tetra-, penta-, and hexa-nucleotides are all <0.001. (d) Gradual loss of genetic diversity (Ht/H0). H0 and Ht represent initial heterozygosity and that after generation t. Solid circles (STR) or triangles (SNP) represent average heterozygosity of individuals from the same generation. P values are calculated based on linear regression.