Identification of Pre-weanling 7-Day-Old Mice with Pinna Edge Biopsies

Identification and genotyping of mice is often an essential part of many in vivo scientific studies. Several methods have been described for identification and genotyping in weaned mice; however, to date, there are far fewer techniques described for pre-weanling mice. Pinna Edge Biopsy (PEB) is a method of identification with subsequent use of tissue for genotyping. This article describes and provides video instruction on a stepwise approach to PEB on post-natal day (PND) 7 mice. Eight different patterns of pinna biopsy location and technique are outlined which have been shown to sustain into adulthood for identification. This article also discusses ways to optimize the PEB and shows the benign effect this technique has on the growth and development of the pups, with all mice showing appropriate weight gain without any morbidity or mortality throughout the study. This technique will provide investigators with a method for mouse identification at an age where there are few identification and genotyping methods available.