Midterm Flashcards
Who was George Price and what was his contribution to genetics?
During
that brief period Price made three lasting contributions to evolutionary theory; these were: (i) the Price
Equation, a profound insight into the nature of selection and the basis for the modern theories of kin
and group selection; (ii) the theory of games and animal behavior, based on the concept of the
evolutionarily stable strategy; and (iii) the modern interpretation of Fisher’s fundamental theorem of
natural selection, Fisher’s theorem being perhaps the most cited and least understood idea in the history
of evolutionary genetics
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 – humans have minimal gene variation
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
Were these mice pregnant or pregnant and in the 3rd trimester when sprayed with pesticides? (ans: NOOOO!) This suggests what about when epigenetic changes can take place?
Epigenetics can take place ANYTIME!!!!
In the Overkalix studies, it was found that nutritional influences and their subsequent epigenetic markers could be transmitted to future generations. 1) When is it thought that these epigenetic effects are imprinted onto the fetus’s of women 2) When can the influence be acquired for transmission by the males. Also, are these the only times epigenetic effects can potentially be acquired by a person, and subsequently transmitted to future generations? (ans: NOOOOO!)
Epigenetic effects are imprinted into women when mother is in utero
Epigenetic effects are imprinted into males at any time
What are the three main problems with trying to determine the cause vs. correlation in genetic disease with genetic studies like the GWAS (slide 27 lecture 1)
Chance, linkage, stratification
Know the 5 points of control and how they work
Chromatin, transcription, translation, post-translation into cytoplasm, post-translation modification
What is a ring chromosome, and what is its significance? How will it read on a karyotype? (what I am asking, is what do the letters coming before the chromosome numbers (r, t, i) each mean). For instance, what does this mean à t(9;22)(q34;q11)
A ring chromosome forms when a deletion occurs on both tips of a chromosome and the remaining chromosome ends fuse together, often resulting in a monosomy
r – ring chromosome
t – translocation
i – isochromosome
What is exon shuffling, and which part (exon or intron?) remains as a section of the mRNA?
EXONS
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?
Methylation
When looking at a cartoon or ideogram of a chromosome, how can you tell the locus from the gene? (essentially know the abbreviations for each. For instance is EPO the gene or the locus? (slide 7 lecture 3)
Locus is the location of the gene, abbreviated by p or q and a number, depending on which arm of the chromosome it is located.
EPO is the gene. Q21.13 is the locus of EPO
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
Know the disease characteristics and pedigree characteristics of the 5 basic modes of inheritance
Autosomal dominant - The locus is on an autosomal chromosome (1-22) and only one mutant allele is required for expression of the phenotype
Autosomal recessive - The locus is on an autosomal chromosome and both alleles must be mutant alleles to express the phenotype
X-linked recessive - The locus is on the X chromosome and both alleles must be mutant alleles to express the phenotype in females
X-linked dominant - The locus is on the X chromosome and only one mutant allele is required for expression of the phenotype in females
Mitochondrial inheritance - The locus is on the mitochondrial “chromosome”
Know the modes of inheritance (i.e. AD, AR, X-linked….. etc.) and what their pedigrees look like (i.e. which show each generation effect, which skip generations)
AD: someone usually affected in each generation
AR: someone affected every other generation.
X-linked R: exhibited usually in males
X-linked D: twice as common in female families.
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)? (slide 13 lecture 3)
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? (Think tumor suppressors vs. proto-oncogenes)
“Loss-of- function” - cause a vital or protective protein to become non- functional in the cell (loss of Tumor Suppressors leads to cancer
“Gain-of-function mutations” occur when either a completely new enzyme is produced in a cell, or more commonly, the enzyme is over produced (proto-oncogenes become oncogenes)
Why is consanguinity important in clinical medicine, even though it is rare amongst Americans?
“Kissing Cousins” – can give rise to genetic diseases (recessive)
