Researchers from many labs collaborated to determine the sequence of the human genome. How did labs avoid sequencing the same fragments multiple times?
|A)||Each lab could isolate DNA from one particular chromosome to divide the sequencing projects.|
|B)||Using restriction fragment length polymorphisms, labs could ensure that they were not sequencing the same fragments.|
|C)||Using short sequences from their respective clones, sequence-tagged sites (STSs), researchers could check to make sure their fragments where not already being sequenced by another group.|
|D)||By comparing sequences from collaborating labs, researchers could ensure that they were not sequencing the same fragments.|
Some of your friends are trying to make sense of their genome. To help them out, you draw an analogy between our chromosomes and the interstate highway system. In this analogy, every interstate represents a single chromosome. How could you describe the relationship between chromosomes and genes to your friends using this analogy?
|A)||Every mile marker would represent a gene.|
|B)||Every town would represent a gene.|
|C)||Every state would represent a gene.|
|D)||Genes would be defined by the twists and turns on the highway.|
Imagine that you broke your mother's favorite vase and had to reconstruct it from the shattered pieces. To do this, you would have to look for pieces with similar ends to join and then progressively glue every piece together. What sequencing strategy does this most closely represent?
Knowing the sequence of an entire genome
|A)||completes our understanding of every gene's function in the organism.|
|B)||allows us to predict the genetic cause of every disease in the organism.|
|C)||provides a template for constructing an artificial life-form.|
|D)||provides the raw data that can then be used to identify specific genes.|
If you were to look at the sequence of an entire chromosome, how could you identify which segments might contain a gene?
|A)||You could identify large protein-coding regions (open reading frames)|
|B)||You could look for a match with an expressed sequence tag (EST)|
|C)||You could look for consensus regulatory sequences that could initiate transcription.|
|D)||All of these strategies could be used to identify possible genes.|
|E)||It is impossible to predict genes from sequence data alone.|
You have been hired to characterize the genome of a novel organism, Undergraduatus genomicus. After fully sequencing the 106 base-pairs in the genome, you predict that this organism has approximately 10,000 genes. You have a collaborator on this project, however, who has identified 20,000 different expressed sequence tags from this organism. How can you resolve this conflict?
|A)||You suggest that your collaborator is an idiot who counted every gene twice!|
|B)||You suggest that your collaborator may have identified multiple isoforms of the same gene that could arise by alternative splicing.|
|C)||You fear that you may have underestimated the number of genes, because you forgot that the organism is diploid and you did not count both copies of every gene in your total.|
|D)||You only identified genes with open reading frames, but most genes do not encode proteins, so your number will be low.|
In addition to coding sequences, our genome contains
|A)||noncoding DNA within genes (i.e., introns)|
|B)||structural DNA involved in telomeres and centromeres.|
|C)||simple repetitive DNA.|
|D)||DNA from transposable elements that have jumped around in the genome.|
|E)||All of these are present in genomic DNA.|
Natural variation in the length of tandem repeat sequences (VNTRs) found in the genome can be used to identify individual people by their DNA fingerprint. Why is this possible?
|A)||The statement is not true; such variability prevents this from being a useful identification tool.|
|B)||The changes in repeat length change the DNA synthesis pattern, so the cell cycles have different lengths, making the cells of different people different sizes.|
|C)||The changes in repeat length occur very infrequently, so there is only one pattern that everybody shares.|
|D)||The changes in repeat length occur very frequently, so everybody has a unique pattern of different lengths when several repeats are examined.|