Final answer:
The researcher studying genetic mutations and aggression in rats likely specializes in behavioral genetics, a field that examines the genetic underpinnings of behavior and its interaction with environmental factors. This includes studying the heritability of traits and behaviors and understanding epigenetic changes over a lifetime.
Step-by-step explanation:
The researcher studying the connection between a specific genetic mutation in rats and the likelihood of aggressive behavior is likely engaged in the field of behavioral genetics. This branch of science explores how individual differences arise through the interplay of genes and the environment. Researchers in this area use various methods, such as twin and adoption studies, to determine the heritability of behaviors and traits.
Behavioral genetics often intersects with sociobiology, a discipline that proposes behaviors and social interactions, like aggressiveness, can largely be explained by genetics and natural selection. This aspect raises the ongoing debate over the contribution of 'nature versus nurture' in shaping an organism. Despite the controversial nature of such claims, numerous studies, including those with rat models, have demonstrated the significant role genetics play in behavior.
Moreover, the concept of epigenetics is central to understanding how gene expression changes throughout a lifetime and across generations due to environmental factors. This could manifest in physical traits or behavioral tendencies that are influenced by genetic factors interacting with the individual's experiences.