It has been known for a number of years that parental genomes are not functionally equivalent. Later studies have identified specific genes which are functionally non-equivalent and such genes are considered to be "imprinted". The best studied cases are in mice although indications are that imprinted genes are found in organisms as diverse as plants and humans. The evolution of such a genetic mechanism is largely unknown. I propose to begin such studies by determining whether the known imprinted genes are imprinted in other eutherians, marsupials and other amniotes, beginning with birds. I will also analyze bison and cow sperm and oocytes as well as pre-implantation embryos from those organisms. The genes known to be imprinted in humans or mice will be cloned from these taxa by the use PCR primers based on conserved gene regions or, if necessary, by other techniques. Imprinting will be determined in various ways and at various stages in all taxa. Insight into the origins and evolution of gene imprinting should be enhanced by this study. %%% The laws of Mendel explain most of what we observe in the inheritance of genetic information. However, observations have been made which cannot be explained by Mendel's laws. One such area is that of imprinted genes; genes which are either expressed or not depending upon which parent contributes the gene copy. Much work is underway to determine the mechanism of imprinting but little or none on the origin and evolution of such a mechanism. This study should give some insight into those questions.
