Genetics, Genomics, and Human Variation Flashcards
A 39 year old woman comes to the physician as she has just learned that she is pregnant. She is offered standard G-banded karyotype, analysis as a prenatal test. Which of the following genetic abnormalities would this best be helpful to establish a diagnosis?
A. a 500,000 bp deletion in a chromosomal
B. trisomy
C. a substitution mutation
D. a frameshift mutation
E. gene duplications
Trisomy
Which of the following describes a human acrocentric chromosome?
A chromosome that possesses repetitive rRNA sequences on one end.
Cells are being studied by light microscopy, and mitiotic spindle fibers attached to the chromosomes are observed. What is the name of this attachment site?
Centromere
A teenage female patient is affected with beta-thalassemia. Molecular diagnosis of her beta-globin genes identifies a mutation that removes the 100 nucleotides immediately preceding the start site for transcription. What beta-blogin regulatory elements is most likely removed by this deletion?
CAAT & TATA boxes
A G-band karyotype confirmed Down syndrome in a 2 year old female patient. Of the choices below, what is most descriptive of the karyotype of this patient?
47, XX
Cells are being studied by light microscopy, and mitiotic spindle fibers attached to the chromosomes are observed. What is the name of this attachment site?
Centromere
A scientist is studying a nuclear gene (POLG) which encodes DNA polymerase-gamma. This gene functions to replicate the mitochondrial genome in a human cell. What part of this gene is not transcribed?
The promoter
A 7 year old boy with a rare form of renal distal tubule acidosis is brought to the physicians. Cells are biopsied and cultured from the patient to facilitate molecular studies. Genetic testing shows a predicted pathogenic mutation thought to affect splicing. The mRNA for the gene is analyzed and it is found that it is larger than the normal form of that transcript. Which of the following would most likely cause aberration?
Mutation of splice donor site of intron 1
The human X-chromosome has more than a thousand protein coding genes on it, and the Y chromosome has only a handful. To maintain balanced gene expression between the sexes:
A. One X-chromosome is deactivated
B. Gene expression from the Y-chromosome is increased
C. Gene expression from each X chromosome in a normal female expresses half
D. The X-chromosome has a lot of genes, but they are not expressed
One X-chromosome is deactivated
SNP
Single Nucleotide polymorphism: relatively common single base pair change which is found in approximately one in a thousand base pairs.
CNV
Copy Number Variant: Describes changes in copy number but does not apply to polymorphic sites such as the SSR, and the VNTR.
LINE/SINE
Long Interspaced Nuclear Elements/Short Interspersed Nuclear Elements. Highly repetitive DNA sequences that are found interspersed throughout the genome. The long ones can create their own reverse transcriptase so that they can make copies of themselves, and propagate in the genome. The short ones have the ability to hijack reverse transcriptase from some other source, and they are also able to propagate in the genome
SSR
Simple Sequence Repeat. A highly polymorphic sequence that consists of di, tri, or tetra nucleotides repeated tandemly in the genome
VNTR
Variable Number Tandem Repeat. These are tandem repeats that are bigger than the SSR, but less than 100s or 1,000s of base pairs. These are polymorphic, but not a variable as the SSR.
LCR
Low copy Repeat. These can be quite large (1,000 bp and bigger) and are found in only a few places in the genome, and they are usually very similar between individuals. General rule: the shorter the repeat sequence, the more variability it is likely to have.
A cytoskeletal component requires ATP for its polymerization and contains subunits that are observed to undergo treadmilling. That cytoskeletal component is a/an:
Actin filaments require ATP for polymerization, and subunits undergo treadmilling as they make their way through an F-actin polymer. Intermediate filaments have stable structures and do not undergo dynamic assembly or disassembly processes. Keratin is a type of intermediate filament. Microtubules are composed of tubulin heterodimers. They require GTP for their polymerization. Additions and subtractions of tubulin from microtubules occur from the same end of the structure.
A 4-year old boy presents in the clinic with signs and symptoms of muscular dystrophy. Testing reveals a small deletion in the dys gene and no functional dystrophin protein. Owing to this defect, which of the following cytoskeletal components is unable to stably bind to the basal lamina in skeletal muscle cells?
Actin Filaments
