Given a sequencing reaction length of approximately 500 successive nucleotides, what is the absolute minimum number of sequencing reactions needed to determine the complete human genome, excluding overlap and redundancy?

Question

A.  3.1 billion
B.  6200
C.  12.4 million
D.  6.2 million

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

  Gather Content
· What do you already know about genome size?

  Consider Possibilities
· Consider the different answer options. Which can you rule out?

  Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

  Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  6.2 million

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses genome size.
· What type of thinking is required?
        o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
· What key words does the question contain and what do they mean?
        o A sequencing reaction is the reaction used to determine the sequence of a piece of DNA.
        o The complete human genome refers to one complete set of 23 chromosomes.

  Gather Content
· What do you already know about genome size?
        o Genome size is highly variable, and not always correlated with organismal complexity.
        o The human genome size is about 3 billion base pairs.

  Consider Possibilities
· Consider the different answer options. Which can you rule out?
        o Would 3.1 billion sequencing reactions cover the genome? Yes, but that is too many. Each reaction could be only 1 nucleotide long and that would be enough!
        o Would 6200 sequencing reactions cover the genome? No, that is not nearly enough. That would only cover 3.1 million base pairs. (6200 x 500 = 3,100,000)
        o Would 12.4 million sequencing reactions cover the genome? Yes, but that is too many. That would cover over 6 billion nucleotides. (12,400,000 x 500 = 6,200,000,000)

  Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The human genome size is 3.1 billion base pairs.
        o Would 6.2 million sequencing reactions cover the genome? Yes, that is the bare minimum number. That would cover 3 billion nucleotides. (6,200,000 x 500 = 3,100,000,000)

  Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to determine the minimum number of sequencing reactions to sequence the entire human genome.
        o The question required you to analyze the information given, using logic, to dissect the problem and determine the answer.
        o Did you remember that the human genome is about 3 billion base pairs long?