Some anthropologists believe that the genetic homogeneity evident in

A at some time in the past our ancestors suffered an event, greatly reducing their numbers ------ A hyphen is not the tool to connect two ICs.
B that at some time in the past our ancestors suffered an event that greatly reduced their numbers -------- ‘that ’ is the right connector ---correct choice.
C that sometime in the past our ancestors suffered an event so that their numbers were greatly reduced ------- altered notion; it looks as if the ancestors suffered a calamity in order to reduce their numbers.
D some time in the past our ancestors suffered an event from which their numbers were greatly reduced -------- conjugation of two ICs with hyphenation is wrong.
E some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly, ------ same as in D

GMATNinja @egmat- I request for clarity on use of hyphenation here and in general for GMAT

Can we take following learning from this question?

dash or hyphen are flexible. They can be used as comma, semi colon, colon . Which one to use in which sceanroes depends on the meaning context. the key is in the part followd by dash or hyphen should make sense. The part can be clause, dependent clause, modifier, phrase, words.


please confirm experts: AjiteshArun GMATNinja EMPOWERgmatVerbal CrackVerbalGMAT EducationAisle GMATRockstar


some reference links:
https://gmatclub.com/forum/what-is-dash ... ml#p816454
https://gmatrockstar.com/2014/01/11/gra ... nd-a-dash/

My problem
Is the sentence structure "... believes that S + V ––– that S + V" interchangable with "... believes that S + V, and that S + V"?

Original OG sentence:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—that at some time in the past our ancestors suffered an event that greatly reduced their numbers and thus our genetic variation.

My revision:
Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck," and that at some time in the past our ancestors suffered an event that greatly reduced their numbers and thus our genetic variation.

Thanks for answering!
Best regards,

Iris

Hi,

Just a quick observation on Option A: at some time in the past our ancestors suffered an event, greatly reducing their numbers; the part 'at some time in the past', isn't this a prepositional phrase? if so how can a clause follow a preposition? Would that not be a reason to eliminate option A.

Regards
AD

Just a quick observation on Option A: at some time in the past our ancestors suffered an event, greatly reducing their numbers; the part 'at some time in the past', isn't this a prepositional phrase? if so how can a clause follow a preposition? Would that not be a reason to eliminate option A.

Hi AjiteshArun,

Following up from your comment, Let me share how I read prepositions and their function in a sentence.

A preposition can modify a noun or a verb depending on the structure.

Ex. In 1947, India attained its sovereignty

In 1947 is modifying the verb attained and is not part of the Independent Clause: India attained its sovereignty

The same could be expressed as In 1947 India attained its sovereignty - in this case we have dropped the ',' however the portion 'In 1947' is still acting as the same function.

In the same way, can we read the option (A) in the OG:

at some time in the past our ancestors suffered an event

Regards
Abheek

Can we eliminate option A on the basis that it doesn???t have ???that??? after the dash?

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of the crucial part of this sentence is that at some time in the past our ancestors suffered an event that greatly reduced their numbers.

Concepts tested here: Meaning + Grammatical Construction

A: This answer choice alters the meaning of the sentence through the phrase "greatly reducing their numbers"; the construction of this phrase illogically implies that our ancestors suffered an event, and as a result, they greatly reduced their own numbers; the intended meaning is that our ancestors suffered an event, and that event greatly reduced their numbers.

B: Correct. This answer choice uses the phrase "event that greatly reduced their numbers", conveying the intended meaning - that our ancestors suffered an event, and that event greatly reduced their numbers.

C: This answer choice alters the meaning of the sentence through the phrase "so that their numbers were greatly reduced"; the construction of this phrase illogically implies that our ancestors suffered an event for the purpose of greatly reducing their numbers; the intended meaning is that our ancestors suffered an event, and that event greatly reduced their numbers.

D: This answer choice alters the meaning of the sentence through the phrase "from which their numbers were greatly reduced"; the construction of this phrase leads to an incoherent meaning; the intended meaning is that our ancestors suffered an event, and that event greatly reduced their numbers.

E: This answer choice alters the meaning of the sentence through the phrase "so as to reduce their numbers greatly"; the construction of this phrase illogically implies that our ancestors suffered an event for the purpose of greatly reducing their numbers; the intended meaning is that our ancestors suffered an event, and that event greatly reduced their numbers.

Hence, B is the best answer choice.

Additional Note: Some students may believe that Options A, D, and E are incorrect because they use a dash to join independent clauses, however, a dash can be used to carry out the roles of a colon, one of which is introducing an independent clause that explains a preceding independent clause, as is the case here. The independent clauses that follow "Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck" are meant to explain what is meant by a "population bottleneck".

All the best!
Experts' Global Team

My only query is why do we need ''that'' after a dash. Isn't this incorrect? I understand that ''that'' act as a subordinating conjunction, so either use ''that'' without ''dash'' or use ''dash'' without ''that''. Why we need both? This was my analysis.

Can you please let me know what's wrong with this analysis?

Regards
Vighnesh