Behavioural Genetics

Behavior pertains to the activities of a living organism in response to its immediate environment or to stimuli released by the body. These activities may be consciously or unconsciously performed. For example, choosing to drink a glass of water is a conscious activity or behavior. On the other hand, sneezing is an unconscious behavior because this is triggered by an external stimulus. Other behaviors include an individual singing or a child running after a ball. The trembling of one’s hands after drinking several cups of coffee is also considered a behavior. These conscious and unconscious activities are influenced by the environment, physiological activities, and genetics.

Background

Scientists in the area of behavioral genetics perform investigations on how conscious and unconscious activities are influenced by genes. One of the most important concepts in behavioral genetics is that behavior is not solely influenced by genes, but by the interaction of genes with the environment. It is particularly important to understand that the term environment in behavioral genetics pertains to all factors that are not inherited. Therefore, the environment consists of family members and friends, the home as well as the workplace, and specific events that have happened in an individual’s life. Other components of the environment may include biological factors such as nutrients, microbial pathogens, and hormones.

Behavioral genetics assumes that genes and the environment surrounding an individual are essential yet interdependent factors that influence behavior. In this field of genetics, research tools that are mainly based on genes are utilized to assess the contribution of different factors to a particular behavior of an individual. Another approach in behavioral genetics is the comparison of the conscious and unconscious activities of various species, starting from the most simple to the actual human being. Behavioral studies have thus been conducted using worms (Caenorhabditis elegans), fruit fly (Drosophila melanogaster), chimpanzees (Pan troglodytes), and human beings. Furthermore, these research investigations overlap with various other fields, including biology, genetics, physiology, and psychology. One particular topic of interest in behavioral genetics is the identification of species-specific behaviors. Other areas of focus in the field of behavioral genetics include those of social significanc, such as mood disorders, impulses, and intelligence. The current society has spent millions of dollars in medical expenses for the diagnosis and treatment of mood disorders. More importantly, members of the family may also be affected by these particular social behaviors and thus it would be helpful if specific genes could be associated with these conditions to better understand the mechanisms underlying these actions.

Impact

One good example of a behavioral genetics topic involves the sensorimotor adaptation of astronauts to spaceflight. First, flying into space entails a significant change in gravity, as the crew members continue on in with their operations for several weeks or months, and then returning to Earth and re-adapting to gravity. Their adaptation to changes in gravity thus require a combination of behavioral, genetic, and brain factors for motor learning, and then recovering normal motor functions upon their return home. The significance of behavioral genetics is realized not only in sensorimotor adaptation during spaceflight, but also for inter-individual differences among crew members to specific techniques and treatments for adaptation to gravity changes. Knowledge and understanding of these differences may facilitate in the design of pre- and post-training techniques that would optimize their productivity and functioning. The identification of factors that could explain inter-individual differences in sensorimotor adaptation to spaceflight may also increase the capacity of the National Aeronautics and Space Administration (NASA) to send individuals to Mars in the coming decades.

The movement of an individual in an environment with altered gravity (e.g., weightlessness in an unstable reference gravity) often induces the development of new sensory patterns in the body. For example, the semicircular canals of the ear, which are the major structures of the inner ear, contain a fluid (endolymph) that contains motion sensors (stereocilia) that transmits electric signals to the brain to indicate that a particular movement has occurred. Therefore, bending, spinning, and moving upward or downward induces the endolymph to lag behind due to its own inertia. The lag in following the direction of movement also bends the stereocilia, which in turn generates an electric signal that is sent to the brain. In the case of crew members on a flight to outer space, the amount of movement involved in being weightless also influences the endolymph of the inner ear to respond to this particular environment. After staying in space for a few days, the components of the semicircular canals have adapted to the weightlessness, thus allowing the crew members to adjust to their flight conditions. However, once these crew members return to Earth, another readjustment occurs, often requiring time to adapt to the current gravitational settings.

Another interesting behavior during space flight involve arm movements. During the initial stages of space flight, crew members often perform physical activities in an inaccurate manner. For example, as an astronaut tries to point to a specific item within their immediate environment in the spaceship, their arm moves toward another area that is not exactly where the item of interest is located. This discrepancy in pointing at items using arms or fingers is largely due to the change in gravity in outer space. Furthermore, the reaction time of arms and fingers are also delayed in outer space. This change in the space of movement is caused by the lack of gravity during flight, and thus adjustments need to be made in order to fulfill all necessary activities while in outer space. It may thus take more time to move around the spaceship during flight. Interestingly, once astronauts return to Earth, they often find that their arm movements and other body movements are faster than what they recall. This particular behavior is mainly due to the presence of gravity on the surface of the Earth, as well as the fact that the brain and the body of a crew member has learned to move in a certain way while in outer space. This adaptation is essential for astronauts to withstand the gravitational conditions during flight.

Bibliography

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