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​Eggs and sperm are highly specialized cells that differ in their shape, size, and how they contribute to fertilization and the development of the new embryo. To achieve these differences, eggs and sperm are created from a specialized cell division called meiosis, which has sex-specific features. Surprisingly little is known about how these sex-specific differences in meiosis come about. Dr. Jaramillo-Lambert, Assistant Professor of Biological Sciences, is using the animal model Caenorhabditis elegans (C. elegans) to understand how each egg and sperm receive the correct number of chromosomes during meiosis and how chromosome shape is determined. If chromosome shape or number is compromised in eggs or sperm, the resulting offspring may fail to develop properly. Previously, Dr. Jaramillo-Lambert’s group identified a mutation in the C. elegans topoisomerase II gene that causes sperm to develop without DNA, which leads to failure in embryonic development and death of the embryo. Interestingly, there are no defects in egg development in female animals with the same mutation. Topoisomerase II is a protein whose normal function is to unknot and untangle DNA as cells go through cell division. How Topoisomerase II works during the cell division of meiosis is not well understood. Dr. Jaramillo-Lambert has been awarded a Maximizing Investigators’ Research Award (MIRA) R35 grant from the National Institute of General Medical Sciences (NIGMS) at the National Institutes of Health (NIH) to identify the components that make sure that Topoisomerase II operates at the correct time and place during meiosis and to identify additional sex-specific components related to meiotic chromosome shape and distribution​.
