Researchers studying how genes
control animal behavior have had
to deal with many uncertainties. In
the first place, most behaviors are
governed by more than one gene,
and until recently geneticists had no
method for identifying the multiple
genes involved. In addition, even
when a single gene is found to control
a behavior, researchers in different
fields do not necessarily agree that it is
a “behavioral gene.” Neuroscientists,
whose interest in genetic research is to
understand the nervous system (which
generates behavior), define the term
broadly. But ethologists—specialists
in animal behavior—are interested
in evolution, so they define the term
narrowly. They insist that mutations in
a behavioral gene must alter a specific
normal behavior and not merely make
the organism ill, so that the genetically
induced behavioral change will provide
variation that natural selection can act
upon, possibly leading to the evolution
of a new species. For example, in the
fruit fly, researchers have identified
the gene Shaker, mutations in which
cause flies to shake violently under
anesthesia. Since shaking is not
healthy, ethologists do not consider
a behavioral gene. In contrast,
ethologists do consider the gene
which controls the fruit
fly’s circadian (24-hour) rhythm, a
behavioral gene because files with
mutated per genes are healthy; they
simply have different rhythms.
1. The passage suggests that neuroscientists would most likely consider Shaker to be which of the following?
A. An example of a behavioral gene
B. One of multiple genes that control a single behavior
C. A gene that, when mutated, causes an alteration in a specific normal behavior without making the organism ill
D. A gene of interest to ethologists but of no interest to neuroscientists
E. A poor source of information about the nervous system
2. It can be inferred from the passage that which of the following, if true, would be most likely to influence ethologists’ opinions about whether a particular gene in a species is a behavioral gene?
A. The gene is found only in that species.
B. The gene is extremely difficult to identify.
C. The only effect of mutations in the gene is to make the organism ill.
D. Neuroscientists consider the gene to be a behavioral gene.
E. Geneticists consider the gene to be a behavioral gene.
I kind of got why OA of the question 1 is correct, but still confused with b.
Both are taking about behavioral genes.
Help me figure out this problem.