Human fetal tissue was staged, collected and dissected by the Laboratory of Developmental Biology (BDRL), utilizing University of Washington IRB protocol 41557. All human tissue was donated with written and informed consent and in compliance with the Health and Human Services Code of Federal Regulations (CFR) 45 Part 46.101–124 (subparts B, D, E). Four human fetal samples were utilized, and these were staged at 113 dpc (unknown gender), 115 dpc (male), 101 dpc (unknown gender) and 96 dpc (unknown gender).
