Marsupials are born at a state that is premature relative to other mammals. For example, most organ systems in a newborn marsupial are developmentally equivalent to those in a 12 week human embryo, which could never survive outside its mother's uterus. In marsupials, the newborn must climb to the teat, where it attaches, suckles, and completes its development. The PI has shown that relative to other animals in marsupials the brain is delayed in development and the bones, cartilages and muscles of the face are advanced. In the current project the PI will examine how early development has been changed to produce the unique specializations of the marsupial. The PI will also compare marsupials to other animals to see how and when these specializations occurred in evolution. The PI will examine the very earliest events in craniofacial development, with special focus on a tissue called the neural crest. Neural crest is particularly important to study, as it is a tissue that originates from the nervous system, but provides most of the cells that make up the facial skeleton.
This study will result in a better understanding of the important differences between marsupial and placental mammals and also to help resolve questions about the evolution of mammalian reproduction. It will also help answer the question of how newborn marsupials can function independently at an embryonic state of development. Finally it will provide basic information on how the brain, bones and muscles of the head are coordinated in development and how development may be changed in evolution.
