Midterm Flashcards
(53 cards)
What was the “one gene hypothesis”? Did it turn out to be correct?
Genes make proteins – one gene = one protein
NO – 1 gene codes for at least 10 proteins
SNPs and other mutations were thought to be the sole cause of human variation, was this assumption correct?
NO – SNPs are not responsible by themselves for humanities large variation phenotypic expression.
How much of the Human Genome is protein coding? How much is RVS?
4% protein coding, 10% retroviral
In what people and country does most of the variability in the human genome still reside?
San Bushmen of East Africa
How are mitochondrial DNA and Y chromosome DNA different, and how are they used in migration studies?
mtDNA changes at a fairly constant rate over time (allowing for aging estimation) while Y chromosome DNA changes/SNP occur in a sequential manner over generations (helps determine when people encountered new areas through migration).
What are the three main problems with trying to determine the cause vs. correlation in genetic disease with genetic studies like the GWAS?
Chance, linkage, stratification
Know the 5 points of control and how they work.
Chromatin, transcription, translation, post-translation into cytoplasm, post-translation modification.
TATA and CCAAT boxes are examples of what.
Promoters
What is exon shuffling, and which part exon or intron remains as a section of the mRNA?
Exons are a segment of DNA that code for a particular protein/peptide sequence.
Exons remain as section of mRNA.
What is the role of enhancers?
Enhancer – a short (50-1500 bp) region of DNA that can be bound by proteins (activators) to increase the likelihood that transcription of a particular gene.
What are the 3 major types of molecular groups that modify histones and cause epigenetic effects?
Methyl, acetyl, phosphate
Which epigenetic marker can attach to DNA directly?
Methyl group
When looking at a cartoon or ideogram of a chromosome, how can you tell the locus from the gene?
Locus: indicated by p or q
Gene: usually acronyms given by their discoverer
What are DNA Marker Alleles? Are they necessarily involved in transcription or biologically active?
Any gene or allele that is associated with a specific chromosome and can be used to identify the chromosome or to locate other genes or alleles.
They are not necessarily directly involved in transcription or biologically active.
What is the difference between the Genotype and the Phenotype?
Genotype - combination of alleles a person has
Phenotype - any observable trait, expressed by genotype
5 basic modes of inheritance?
Autosomal dominant Autosomal recessive X-linked dominant X-linked recessive Mitochondrial
What did the story about Koko and her kitty cat suggest about human behavior?
Behaviors like deception are likely inherited traits from the animal kingdom.
Disease and pedigree characteristics of autosomal dominance?
Person needs only 1 copy of the gene or the allele to be mutant in order to have the trait, characteristic, or disease to be expressed.
Expressed in every generation.
Disease and pedigree characteristics of autosomal recessiveness?
Person needs to have 2 copies of the gene or allele to be mutant in order to have the trait, characteristic, or disease to be expressed.
Typically observed in only 1 generation of a pedigree (may skip).
What are the characteristics of X-linked Dominate diseases? Can they be transmitted from father to son? Can they be transmitted from father to daughter?
X-linked dominant disease are twice as common in females than males, because a father cannot transmit to his son, but only his daughter (father does not give X chromosome to son)
Why can males get X-linked recessive diseases with just one mutated allele? (Normally two disease alleles are needed to manifest a recessive disease)?
Males only have one x chromosome.
What is the difference between a missense mutation and a nonsense mutation?
Missense – single base change in the gene that leads to a change in the codon that encodes for one amino acid.
Nonsense – a base change that results in a “stop codon” – a short and completely inactive protein/enzyme.
What is the difference between a gain-of-function and a loss-of-function mutation, and is one necessarily less troublesome than the other?
Loss-of- function: causes a vital or protective protein to become non-functional in the cell (e.g. loss of tumor suppressors leads to cancer).
Gain-of-function: occur when either a completely new enzyme is produced in a cell, or more commonly, the enzyme is over-produced (e.g. proto-oncogenes become oncogenes).
Loss of function are more commonly associated with severe diseases.
Why is it called fragile X syndrome, and what determines its severity?
Most common cause of mental retardation due to a number CGG repeats, which determines severity (higher number of CGG repeats = greater severity).
Name is due to one arm of the X chromosome a-danglin’.
