Behavioral Genetics Case Study
Behavioral Genetics Case Study
We measure behavior in
the field and lab
There are, of course, advantages and disadvantages for both
• We can conduct analyses under “true” environments and conditions • We can observe behaviors that give us a lot of insight into how a particular group
works • But we can’t experimentally manipulate
In the field:
• We can control things like temperature, humidity, light/dark cycle, diet, social environment, age, breeding, genetics, etc.
• But it’s hard to generalize our findings to more populations, given this control and specific testing populations
In the lab:
Behavioral Assays in
Mice and Rats
• Monitors spontaneous exploratory behavior when an animal is placed in an enclosure
• Video-recorded, and therefore allows for measurement of total activity, average speed, number of activity bouts, etc.
• Example: Mice are recorded in an enclosure with a bright and dark area, and time spent in each area is measured. Mice are nocturnal, and choosing an area of bright illumination over the dark area is a sign of boldness, whereas the opposite is interpreted as anxiety.
Open field test:
• Animals are trained to use visual cues to swim toward a hidden platform in a circular pool
• It measures spatial navigation and memory
Morris water maze:
Behavioral Assays in
Mice and Rats
• Placing a running wheel in an animal’s cage can measure spontaneous endogenous locomotor activity
Running wheel
• Measures balance by placing rodents on a slowly revolving rod – literally measure the time it takes for the rodent to fall off, as a measure of balance
• Can assess the effects of mutations on proprioception and postural control
Rotating rod
• Assesses an individual’s preference for a particular substance (usually a drug) by providing an animal a choice of a container that holds the substance vs. a water control
Preference tests
Controlling experimental variation
To minimize variation, it is essential to conduct studies such that
measurements are completed at the same time of day, and under
controlled conditions of temperature, humidity, air flow, and
illumination
Behaviors of sexes should be measured separately
Diet and age should be standardized
Sexual experience of animals (virgin, pregnant, or sexually-
experienced) can also influence behaviors
Social environment should be controlled (animals in isolation
behave differently than those in crowded conditions)
Genetic background can be a variable, so in animal studies,
comparing litter mates and inbred strains can be helpful, or using
twins in human studies
Sources of variation in
behavior: Genetic Variation
