Table 2. Summary of evolution events of Drosophila sperm nuclear basic protein (SNBP) genes.

Name	Phenotype	Age (My)	Expression level (TPM)*	Evolutionary rate (dN/dS)†	Positive selection(MK test)‡	Amplification event(s)§	Number of loss events in 80 species¶	Number of loss events in the montium group(X-Y fusion)
CG30356	Undefined	>65	353	0.39	+	0	1	0
CG31010	Undefined	>65	346	0.35	+	1X	1	0
CG34269	Undefined	>65	49	0.34	+	0	2	5
CG42355	Undefined	35	532	0.36	+	0	0	0
Mst33A	Undefined	35	632	0.43	-	1Y	1	1
ddbt	Sterile	>65	130	0.35	-	1X	3	0
Mst77F	Sterile	35	3636	0.45	-	1Y	3	1
Prtl99C	Sterile	45	540	0.30	-	2X	4	2
CG30056	Fertile	>65	406	0.10	-	0	0	0
CG14835	Fertile	>65	432	0.36	-	1X	3	1
Tpl94D	Fertile	45	564	0.41	+	0	2	0
Prot	Fertile	>65	1118,1619	0.21	+	2A;1X;2Y;4X/Y;1U	0	0
tHMG	Fertile	>65	935,1194	0.39	+	2X; 1U	5	1

^* Gene expression level in D. melanogaster testes (Supplementary file 2).

^†dN/dS in D. melanogaster subgroup species (Supplementary file 4).

^‡Positive selection based on McDonald–Kreitman tests in D. melanogaster and/or D. serrata.

^§Any specific location with five or more copies of any one SNBP gene. A represents all autosomes combined, X represents the X chromosome, Y represents the Y chromosome, X/Y represents either the X or Y chromosome, and U represents regions with unknown chromosome locations.

^¶Number of potential loss events inferred by the phylogeny (Figure 3 and Figure 3—figure supplement 1). Some of these may represent false negatives due to incomplete genome assemblies.