Ch 15 LC
Terms in this set (34)
Any mutation that has no effect on the organism is considered what
What are short repeated sequences of DNA that vary in number from one chromosome to the next?
Variable number tandem repeats
Gel electrophoresis is the preferred method for detecting single nucleotide polymorphisms. true or false?
Nondisjunction in the sex chromosomes is more severe than in the autosomes. true or false?
a) can be subject to environmental conditions.
b) only result from gene transcription.
c) are always expressed in the same way.
d) always result solely from the actions of a single gene.
e) None of the answer options is correct.
A) can be subject to environmental conditions.
Much of the genetic variation seen in the human population is what?
A newly arisen point mutation always creates a SNP (single nucleotide polymorphism). true or false?
There are no discernible phenotypic effects for an individual with what genotype?
An organism that has two different alleles of a given gene has what genotype?
What is an advantage of DNA typing?
Only small amounts of DNA are needed.
SNPs within a gene called FOXO correlate with increased longevity in humans. You are a researcher in a lab and wish to determine if you possess this SNP. Based on this correlation, where must the SNP be located in the genome in relation to the FOXO gene?
It is impossible to tell without further analysis
What is it called when sister chromatids fail to separate during anaphase of cell division?
If an individual is homozygous for a certain allele, it means that:
the individual received the same allele from each parent.
What explains the difference between VNTRs and RFLPs?
In VNTRs, we are looking at the number of times a sequence is repeated; in RFLPs we are looking at size differences resulting from different restriction sites being present.
For any SNP, what is the maximum number of alleles possible?
The occurrence of nondisjunction during mitosis can result in the development of certain ______; however, nondisjunction is often thought of in relation to meiosis and the development of certain _______.
Genetic studies have identified an allele (Δ32) that seems to provide protection against HIV. Which of the following would most likely explain the reason why our population has this mutation?
This mutation likely benefited the human population against some other related pathogen
After doing PCR on the same region between two individuals, you notice that each person's DNA yielded pieces of different sizes. What is the most likely explanation?
This is an example of VNTRs.
The biggest difference between CNV and VNTRs is what?
the size of the DNA being studied
Trisomy 21 (Down syndrome) is the only example of an autosomal trisomy in which the fetus develops to term and is born alive. true or false?
Until 20 or 30 years ago, people with cystic fibrosis (CF) wouldn't live long enough to reproduce. CF is a homozygous recessive condition, leading researchers to think that over time the incidence of CF would decrease because the allele would be removed from the gene pool. The results actually indicate that the rate of CF is on the rise. Based on what you know about why certain genotypes and phenotypes persist in a population, what could be a likely explanation for why the rate of CF is on the rise?
The heterozygous condition is beneficial, much like what we see with sickle cell trait.
Imagine that you are a detective who has identified a suspect in a homicide. You acquire a small amount of blood from the crime scene and hand it over to your lab. The lab carries out PCR for one polymorphism, and it returns as a match to your suspect. Is this enough to arrest your suspect?
No, your lab should assess additional polymorphisms; a single polymorphism does not constitute a DNA fingerprint.
A phenotype always refers to something that you can see with your eyes, like hair color or eye color. true or false?
A patient is about to receive chemotherapy and the doctor is concerned with dispensing the correct dosage. Certain people cannot metabolize this type of chemical because they have a mutation that changes a codon for valine into one for aspargine. How would such a mutation be classified?
What is true regarding RFLPs?
A polymorphism results in one site being recognized by a restriction enzyme, but not in others
The ability to perceive a bitter taste from certain chemicals including PTC has been linked to certain alleles. What would provide an explanation for the fact that almost all nonhuman primates have the "taster" phenotype, whereas the human population has a significant percentage of "nontaster" phenotypes?
The advantage to being able to taste bitter compounds would keep you from eating poisonous compounds, an advantage not needed in the human population anymore.
SNPs arise from:
For a SNP with three alleles, how many different diploid genotypes are possible?
Imagine that you know two sisters—Rose and Sam—both of whom smoke. Rose has a mutation in the gene for alpha-1 antitrypsin, whereas Sam does not. What is true regarding these sisters?
It is possible that neither Rose nor Sam will develop emphysema; however, the fact that both sisters smoke—added to the mutation that Rose carries—increases their chances of developing this disease.
The number of tandem repeats in an individual will:
vary from chromosome to chromosome.
While a mutation will not always change the ________ of an individual, it will always change the _________
The difference between a single nucleotide polymorphism (SNP) and a point mutation is that:
a point mutation is when a base pair is changed to a different base pair, whereas a SNP is when the base pair differs among individuals in a population.
CNVs are chromosomal mutations that are always due to duplications. true or false?
What explains why restriction enzymes are not useful for genome-wide studies of genetic variation?
Using restriction enzymes will only tell us differences in sequence variation in restriction site