Biology Reference
In-Depth Information
behavior and physiology can be particularly difficult. The same behavior can be
examined from at least four different viewpoints: 1) the immediate cause (or
control), 2) its development during the individual's life span, 3) the function of
the behavior, and 4) how the behavior evolved (
Wyatt 1997
).
Behavior genetics began to develop as a field of study in the 1960s, but was
limited to demonstrating that a behavioral trait was heritable, determining
whether its
mode of inheritance
was dominant or recessive, sex-linked or auto-
somal, and resolving whether the variation was due to single or multiple genes
(
Ehrman and Parsons 1973
). Genetic analyses of insect behavior require careful
control of environmental conditions, because even subtle differences in test con-
ditions can influence the results of assays (
Vanin et al. 2012
). Objective measures
of insect behavior are difficult, and considerable efforts have been devoted
to devising specific and appropriate assays. The possible influence of learning
always must be considered and, to complicate matters further, learning rates
no doubt vary among different populations of the same species so that both
heredity and environment must be considered. Furthermore, recent studies indi-
cate that individuals within a population may vary in their behavior and have
“personalities”; for example, some may be more adventurous than others.
Genetic analyses of insect behavior involve, in many cases, analyses of the
physiological or morphological changes that are associated with the change
in behavior. Sometimes, however, behavior is changed in an insect because a
morphological trait has been altered through mutation.
The genetic basis of insect behavior has been analyzed most extensively using
Drosophila melanogaster
and a few other species, such as honey bees, grasshop-
pers,
Nasonia
parasitoids, and crickets (
Benzer 1973, Matthews and Matthews
1978, Ehrman and Parsons 1981, Hall 1984, Kalmring and Elsner 1985, Huettel
1986, Huber et al. 1989, Menzel 1999, Beukeboom and van den Assem 2001
).
Molecular-genetic techniques provide powerful methods to analyze insect
behavior, including olfaction, learning, circadian rhythms, and mating behav-
ior. Having the complete sequence of the genome of
D. melanogaster
simplifies
the isolation of specific genes that are involved in the behavior.
P
-element-
mediated transformation makes it possible to insert genes from one species of
Drosophila
into the genome of another, and their effect(s) on behavior can be
determined. Transgenic
D. melanogaster
carrying markers such as green fluores-
cent protein (GFP) allow scientists to determine when and where specific genes
are active.
Molecular-genetic analyses of learning and memory in
Drosophila
pro-
vide a means to study one of the most challenging frontiers in neurobiology
