Researchers studying how genes control animal behavior have

Question

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 Shaker a behavioral gene. In contrast, ethologists do consider the gene period (per), which controls the fruit fly’s circadian (24-hour) rhythm, a behavioral gene because flies with mutated per genes are healthy; they simply have different rhythms.   1 
 A 
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 
 C 
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.

3 
 B 
The primary purpose of the passage is to
A. summarize findings in an area of research
B. discuss different perspectives on a scientific question
C. outline the major questions in a scientific discipline
D. illustrate the usefulness of investigating a research topic
E. reconcile differences between two definitions of a term

Note:  Verbal OG 2019 question order is #3, #1, #2
RC00322-01
RC00322-02
RC00322-05

AashishGautam · Answer

Hi GMATNinja

can you explain the error in this line of reasoning with respect to question 1
I choose answer option D, here's my reasoning.

Firstly Given,
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  .

Now since neurologists define this research broadly, they might not consider this important at all.
Hence, this was the only OA that made sense to me.

Secondly considering your line of reasoning,

I am confused that the difference between Neurologists and ethologists is in defining the terms broadly & narrowly, not altogether a contrast.

Please explain, this seems to be eating my head :-/

Deadpool3 · Answer

Hi  GMATGuruNY  ,  VeritasKarishma ,  ChiranjeevSingh ,  Skywalker18 ,  egmat ,  TheEconomistGMAT ,  GMATNinjaTwo   GMATNinja   generis   hazelnut   mikemcgarry

Could you please clarify the logical gap that I am inferring in the passage.

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 Shaker a behavioral gene . In contrast, ethologists do consider the gene period (per), which controls the fruit fly’s circadian (24-hour) rhythm, a behavioral gene because flies with mutated per genes are healthy; they simply have different rhythms.

In the above highlighted text, Since Fruit fly is shaking means a behaviour change, plus shaking is not healthy -->Shouldn't this lead to inferring it as behavioral gene

Since,  Ethologists --> behaviour change + make ill --> behavioral gene

KarishmaB · Answer

... ethologists—specialists in animal behavior—are interested in evolution, so they define the term (behavioral gene) 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 Shaker a behavioral gene. In contrast, ethologists do consider the gene period (per), which controls the fruit fly’s circadian (24-hour) rhythm, a behavioral gene because flies with mutated per genes are healthy; they simply have different rhythms.

As per ethologists, a behavioral gene is that in which mutations alter normal behaviour e.g. period gene which controls the circadian rhythm. A mutation in this changes the fly's rhythm. So now natural selection can possibly lead to the evolution of a new species with a different rhythm. 
As per ethologists, genes in which mutations only make the organism ill are not behavioral genes e.g. shaker gene. Mutations in shaker genes cause the fly to shake violently under anaesthesia (makes the fly ill) but does not change its normal behaviour (the things the fly does when normal and awake). Hence, as per them, gene shaker is not a behavioral gene.

Normally one would think that a mutation in a gene would cause the organism to be ill. That is why the author writes "... mutations in a behavioral gene must alter a specific normal behavior  and not merely make the organism ill ". Whether mutations in behavioral genes actually do make the fly ill too, we can't say. The distinction between non behavioral gene and behavioral gene (as per ethologists) is that a mutation in behavioral gene causes changes in behaviour which natural selection can choose to favour to bring new species.

Neuroscientists, whose interest in genetic research is to understand the nervous system (which generates behavior), define the term broadly. So we can assume that both genes would be called behavioral genes as per neuroscientists.

saby1410  - Hope it answers your question too.

GMATNinja · Answer

The passage does set up a contrast between how neurologists and ethologists define "behavioral genes."

Ethologists are looking for a very particular set of criteria in a behavioral gene. They think that to qualify as a behavior gene, that 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."

This is a  more narrow  definition than the one used by neurologists. Neurologists will call a gene a "behavioral gene" if that gene controls a behavior -- they don't care exactly  what  that behavior is.

Let's say that there is a gene that just makes an animal get violently ill when it goes into the sunlight. A neurologist would call this a behavioral gene, because it controls the behavior of the animal. An ethologist, on the other hand, would NOT call this a behavioral gene. Because this particular gene just makes an animal sick, it does not provide variation that natural selection can act upon.

The gene discussed in question 1 is very similar to the example above. Ethologists would NOT consider it a behavior gene, but neurologists most likely would.

Here's (D):
 
From the above analysis, we know that neurologists would consider Shaker to be a behavioral gene. There's no way we can infer from this that they would  not  be interested in Shaker -- if anything, the passage implies that they WOULD be interested in Shaker because it fits their definition of behavioral gene.

(D) is out and (A) is the correct answer to question 1.

I hope that helps!

Will2020 · Answer

GMATNinja Why can't we use the exactly same explanation you gave above to choose (A) to pick (D) on the second question ? The only thing I can think about is that since the neuroscientists define the term broadly, their definition could encompass the definition of ethologists, so ethologists may agree or disagree about whether a gene being a behavioral one. In that sense, the neuroscientists view about a behavioral gene would influence the ethologists' opinions ONLY sometimes, only in the case when Neuroscientists consider the gene to be a behavioral one and also when their is evidence that the Shaker becomes ill. Does that make sense to you? Thank you!

GMATNinja · Answer

Remember, you need to treat each question on an RC passage individually. Just because the two questions sound similar doesn't necessarily mean you'll use the same technique to solve them.

There's a full explanation of why (D) is not the correct answer to question 2 in  this post .

To answer your question, just because the neuroscientists and ethologists have DIFFERENT definitions doesn't mean that one of those groups INFLUENCES the other. It's totally possible that the ethologists think that neuroscientists are total idiots and that the neuroscientists' definition is just wrong. Nothing in the passage implies that one group influences the other despite their differences of opinion.

I hope that helps!

Will2020 · Answer

DmitryFarber VeritasKarishma mcelroytutoring Regarding question 2, I understand why C is the correct AC, but I can NOT understand why D is wrong? If ethologists and neuroscientists have contrasting definitions regarding behavioral gene, why the neuroscientists opinion can not influence the ethologists opinions about whether a particular gene in a species is a behavioral gene? Didn't we assume that to answer question 1? Many tks!

KarishmaB · Answer

Neuroscientists define the term "behavioral gene" broadly. But ethologists define a behavioural gene as that in which mutations alter normal behaviour, not just cause sickness. 
So whether Neuroscientists consider the gene to be a behavioral gene is irrelevant to the ethologists. They have their own criteria.

Vishalcv · Answer

Hi  GMATNinja

I chose option A for the 3rd question. It isn't a popular option, but I went with it because the passage, almost entirely, describes how Ethologists determine if a gene is Behavioural or not, using examples. There are hardly a few words describing other perspectives. So how can it be B?

GMATNinja · Answer

Question 3 
 
To answer primary purpose questions, think about  why  the author wrote the passage in the first place.

Here, the author discusses two groups of researchers, and contrasts their definitions of a certain term. Then the author cites an example to further explain one of those definitions.

So yes, the author spends a good amount of time summarizing the ethologists' point of view. However, the  purpose  of that summary is to provide a contrast to the view of the neuroscientists. So, (A) really doesn't capture the author's primary purpose.

I hope that helps!

Namangupta1997 · Answer

HI  GMATNinja

What is wrong with option E of question 3? The passage does highlight the differences between how neurologists and ethologists DEFINE a particular term. So the  definitions  of that term are being discussed.

GMATNinja · Answer

Question 3 
 
To answer primary purpose questions, think about why the author wrote the passage in the first place.

Here, the author discusses two groups of researchers, and contrasts their definitions of a certain term. Then the author cites an example to further explain one of those definitions.

Take another look at the exact wording of (E):
 
Yes, the author discusses two definitions of a term, as you've mentioned.

However, the author never  reconciles the differences  between these two definitions. He/she just tells us how the two groups define the term, and never brings those two definitions together. That's why (E) is out for question 3.

I hope that helps!

a123bansal · Answer

Hello  GMATNinja   KarishmaB

I have a basic doubt. Requesting your help on this.

In C option, Is "Scientific disciple" mean "Scientific area of discussion" or something else?

Thank You

GMATNinja · Answer

Yes, you're on the right track. A "scientific discipline" is just a subject that is studied by scientists. Hopefully that helps a bit!

HC1993 · Answer

GMATNinja  - When this question says influence, does it mean an option that could weaken the perspective?

GMATNinja · Answer

Question 2 
 
In this context, "influence" doesn't mean "weaken the perspective." Instead, the question is just asking us which factor the ethologists would consider to be influential in deciding whether something is a behavioral gene.

Consider this example: maybe I think that the best brunch spots offer dosas. What would influence my opinion on a particular brunch spot? Well, if that spot doesn't offer dosas, that would definitely influence my opinion. I'd be influenced not to go to that place. My overall perspective isn't weakened -- I'm still committed to the idea that a good brunch spot is defined by the presence of dosas.

Similarly, ethologists believe that "mutations in a behavioral gene must alter a specific normal behavior and not merely make the organism ill." So, what would influence their opinion on whether a certain gene is behavioral? Well, if they learned the info in (C) ("The only effect of mutations in the gene is to make the organism ill,"), then they would definitely think that the gene in question is NOT a behavioral gene. So, that information would influence their assessment.

That's why (C) is the correct answer to question 2.

I hope that helps!

waytowharton · Answer

KarishmaB   GMATNinja  Sir/madam can you help in Q3-Primary purpose question.

The primary purpose of the passage is to
A. summarize findings in an area of research
B. discuss different perspectives on a scientific question

I have doubt why Option A is incorrect. Summarize findings in an area of research that is how genes control animal behavior. We have 2 findings i.e. most behaviors are governed by more than one gene and researchers in different fields do not necessarily agree that it is a behavioral gene.

Whereas Option B is a derivative of passage it doesn't cover entirety. It just focuses on researchers in different fields do not necessarily agree that it is a behavioral gene.

KarishmaB · Answer

The primary purpose of the passage is to
A. summarize findings in an area of research
B. discuss different perspectives on a scientific question
C. outline the major questions in a scientific discipline
D. illustrate the usefulness of investigating a research topic
E. reconcile differences between two definitions of a term

Here is the thing - the passage provides us no "findings"

What is a "finding" - Researchers have found that most behaviors are governed by more than one gene.

What does the passage say? "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."

So it is given as a fact - that since behaviours are governed by more than one genes, and until recently, researchers didn't know how to identify those genes. 
So perhaps now they are able to identify but what have they found using this tech, we are not given.

Then the entire rest of the passage talks about how researchers in different fields do not agree on how to define a “behavioral gene.” 
There is no finding discussed here too. Hence answer is not (A).

By elimination of options, the best option is (B) since the passage, after its first two lines, focusses on explaining how researchers in different fields have different ideas on "what is a behavioral gene?”

Also note that there is no "outlining of major questions," no "illustrating" and no "reconciling" done.

Answer (B)

Apeksha2101 · Answer

What does question asking, I dont understand what do they want from INFLUENCING

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?

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Researchers studying how genes control animal behavior have

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