Table S1.

Lengths of comet tails in ground and space-preserved spermatozoa

Mouse strain	Condition of preservation*	No. of spermatozoa	Average length of comet tail†	SD	P value, Wilcoxon–Mann–Whitney test
C57BL/6	Ground	93	1.00	0.16
	Space	93	1.002	0.28	>0.2
BDF1	Ground	392	1.00	0.20
	Space	392	1.28	0.21	<0.001
BCF1	Ground	238	1.00	0.23
	Space	238	1.03	0.25	<0.001
129B6F1-GFP	Ground	111	1.00	0.32
	Space	111	1.48	0.39	<0.001

^*Ground: At the same times and for the same durations as when launching and storing the sample case, a control sample case was exposed to room temperature, then frozen at –95 °C and stored in a freezer at the Tsukuba Space Center in Japan. These are referred to as ground control sperm samples. Space: Samples were launched and stored on the ISS for 9 mo.

^†To standardize the results between different mouse strains, the lengths of each DNA comet tail were divided by the mean length of the ground control results in each strain.