Sample_12_0724 Mouse NCBI GEO/SRA Primary cell Spermatogonia_from_testis TSPAN8-high subpopulation of P6 ID4-EGFP+ Sample_12_0725 Mouse NCBI GEO/SRA Primary cell Spermatogonia_from_testis TSPAN8-low subpopulation of P6 ID4-EGFP+