Biology Reference
In-Depth Information
Mackay concluded, “If a substantial fraction of the genome can affect any single
trait, it follows that most genes must be pleiotropic and affect multiple traits.”
Edwards et al. (2009)
screened 170
P
-element insertions for quantitative differ-
ences in aggressive behavior from their isogenic control line of
D. melanogaster
and identified 59 mutations in 57 genes that affect aggressive behavior, none
of which previously were found to affect aggression. Among the 59 mutations,
32 resulted in increased aggression, and 27 lines were less aggressive than the
control.
Edwards et al. (2009)
found, “Many of the genes affect the development
and function of the nervous system
…
Others affect basic cellular and metabolic
processes.
…
” The genes had pleiotropic effects on brain morphology.
Dierick and Greenspan (2006)
analyzed aggressive behavior in
D. melanogas-
ter
by selecting populations in a two-male arena assay. After 10 generations of
selection, the aggressive lines became more aggressive and after 21 generations,
the fighting index increased
>
30-fold. Microarray analysis indicated at least
42 genes were affected, but most of the expression changes were small, with only
four genes showing an expression difference greater than two-fold. Six genes
were then analyzed by quantitative PCR and five of the six had expression pro-
files that matched the microarray results. The differences in results obtained by
Edwards et al. (2009) and Dierick and Greenspan (2006)
are likely due to differ-
ences in experimental design.
11.10 Social Behavior in Bees and Ants
Honey bees and ants are eusocial insects and a great deal of controversy sur-
rounds the evolution of sociality (e.g.,
Nowak et al. 2010, Bloch and Grozinger
2011
). Rapid advances in understanding the social life of
Apis mellifera
are
being made now that the genome has been sequenced. For example,
Liang
et al. (2012)
documented that scouting behavior for food and nest sites varies
among workers and identified the genes involved in this behavior using whole-
genome microarray analysis and quantitative reverse-transcriptase polymerase
PCR.
Liang et al. (2012)
concluded, “Our results demonstrate intriguing paral-
lels between honey bees and humans in novelty-seeking behavior. Although
the molecular mechanisms that produce this behavioral variation are similar, it
is unknown whether both species inherited them from a common ancestor or
evolved them independently.”
Whitfield et al. (2006)
analyzed the process by
which workers mature from working in the hive to foraging using gene-expres-
sion microarrays of the bee brain.
Jarosch et al. (2011)
found how Cape honey bees,
Apis mellifera capensis
,
have modified their biology so that workers can reproduce by thelytoky,
