Biology Reference
In-Depth Information
of sleep in
Drosophila
is complex and controlled by multiple brain circuits involv-
ing sleep duration, waking activity, and number of sleep bouts.
Soshnev et al.
(2011)
found that a conserved long noncoding RNA called
yar
affects length of
sleep, disruption of sleep, and that it may regulate sleep by affecting stabiliza-
tion or translational control of mRNAs.
11.8 High-Throughput Ethomics
The study of insect behavior can be very labor-intensive. A common method of
analysis involves videotaping an insect's behavior, then analyzing the tape frame
by frame. A camera-based system was developed to automatically quantify indi-
vidual and group behaviors of
D. melanogaster
and to provide automated anal-
yses of the data obtained (
Branson et al. 2009
). The system allows analysis of
individuals or of groups of flies, allowing high-throughput screening. Another
automated-monitoring system for analysis of
Drosophila
behavior was devel-
oped by
Dankert et al. (2009)
. It also provides software that allows analysis of
both single flies and groups of flies.
Reiser (2009)
hailed the development of
these two systems that enable high-throughput screens that will allow scientists
to resolve cellular and molecular underpinnings of behavior. The systems involve
video recording of behavior, detection of flies in each frame, assignment of
the trajectory, and classification of the behavior into an “ethogram.” An etho-
gram is a catalog of the action patterns in an animal's behavioral repertoire.
Both systems are freely distributed, and may be useful with insects other than
D. melanogaster
.
11.9 Systems Genetics of Complex Traits in
Drosophila
The ability to sequence genomes relatively inexpensively has allowed analysis of
complex behaviors in
D. melanogaster
(
Ayroles et al. 2009, Edwards et al. 2009,
Mackay 2009
). What is system genetics? It is the use of
P
-element mutagenesis
to identify genes affecting complex behaviors, artificial selection of natural pop-
ulations to create extreme phenotypes, high-resolution mapping to identify can-
didate genes corresponding to quantitative trait loci (QTLs), and whole-genome
transcriptional profiling to identify networks of interacting genes affecting
complex traits (
Mackay 2009
).
Mackay (2009)
concluded that large numbers of
loci affect behaviors in natural populations of
D. melanogaster
, including olfac-
tory-avoidance behavior in response to a single odorant (97 mutations). In stud-
ies involving
P
-element insertions into the genome, 17% of the genome was
involved in the effects of ethanol on
D. melanogaster
, and 34% of insertions
affected locomotor behavior. Whole-genome transcript analyses of lines indi-
cated that 530 genes were affected by a single mutation in
smell-impaired
loci.
