Fig. 7: Evolutionary metrics of nitrogen fixation genes.
From: Phylogenetically and catabolically diverse diazotrophs reside in deep-sea cold seep sediments
a Nucleotide diversity (π) of nifHDK genes at different types of cold seeps; b pN/pS ratio of nifHDK genes at different types of cold seeps. Nucleotide diversity is used to measure genetic diversity within a population (microdiversity), which is calculated using the formula: 1 − [(frequency of A)2 + (frequency of C)2 + (frequency of G)2 + (frequency of T)2]. pN/pS is the ratio of non-synonymous to synonymous polymorphism rates within a population. n values refer to the number of biologically independent samples for statistics analysis. The significances were analyzed by two-sided Kruskal–Wallis Rank Sum test. Boxplot components: center line, median values; box limits, upper and lower quartiles; whiskers, 1.5× interquartile range; points, outliers. Source data are provided as a Source Data file.
