The Gray Short-Tailed Opossum (Monodelphis domestica) in Biomedical Research

The gray short-tailed opossum (Monodelphis domestica) is a pouchless marsupial native to South America. Its small size, docility, and year-round breeding ability have made it a widely used model for biomedical and evolutionary research. In addition to a high-quality genome, there are several transcriptome libraries available for this species, and numerous common molecular techniques have been adapted for the opossum.

The opossum is born with well-developed forelimbs, permitting its climb to the mother’s teats to complete development. The hind limb is rudimentarily formed at birth. This limb disparity has been used as a ‘natural mutant’ for studies of mammalian limb formation and evolution. Opossums, like humans, are susceptible to in utero retinoic acid teratogenesis. Retinoic acid causes forelimb oligodactyly, shortened limbs, and craniofacial defects in opossums. The unique biology, natural limb disparity in the fore- and hind limbs, and susceptibility to limb malformations make the opossum an excellent model for studying human developmental defects, in particular those of the limbs. Additionally, the opossum has been used by other labs in studies of spinal regeneration, wound healing, and melanoma to name a few fields. Thus the opossum is a versatile model in a number of human-health fields.

Currently, there is no way to modify the genome of the opossum via knockout or transgenic technologies, a drawback in using the opossum. Our lab is currently working to develop these techniques using spermatogonial stem cell (SSC) transplantation. Briefly, SSCs are collected from the testes, purified and expanded in culture, modified, and transplanted into a recipient male.