Mod 8-10 Flashcards
whole set of genes of individuals
genome
modification of ________ leads to changes in gene expression and may alter individul traits or phenotype
base sequences
alterations that do not involve changes in an individual’s base sequence but still effect gene expression
epigenome
“epi” in epigenome means
above
________________ can detect the turning on and off of genes
epigenetic marks
changes in the regulation of gene activity and differential expression of genes including differences in the pattern and timing of genetic switches are considered
epigenetic
the term “epigenetics” was coined by ________________
Conrad Waddington
epigenetics follows <blank> which proposed that the early embryo was undifferentiated</blank>
theory of “epigenesis”
the branch of biology which studies the causal interactions between genes and their products which brings the phenotype into being
epigenetics (Waddington)
the study of mechanism of temporal and spatial control of gene activity during the development of complex organism
epigenetics (Holliday)
study of changes in gene expression that occur not only by changing DNA sequence but by modifying DNA methylation and remodeling chromatin
Epigenetics [Holliday (?)]
Mitotically and/or meiotically heritable changes that could not be explained by DNA base sequence changes
Epigenetic changes (Wu and Morris)
TRUE OR FALSE: Most cells in a multicellular organism like man, have an identical genome, however, these cells do not become differentiated and commit to specific functions
FALSE: they become differentiated
includes stable and long-term alteration in the transcriptional potential of a cell that MAY NOT necessarily be heritable
epigenetics
affects the ACCESSIBILITY of the genome at the right place and at the right time
Epigenetic mechanisms
determine which genes will be turned off or on. It also regulates the degree of expression at a particular time given a particular environmental condition
Epigenetic factors
<blank> is stable and reveals our inherited genetic identity.
</blank>
DNA Structure
TRUE or FALSE: There is an interplay between our genome and the environment and signals from the environment that can lead to such epigenetic marks effecting the differential switching of genes even among twins
True
<blank> attached to DNA and epigenetic factors in histone tails activate or repress genes
</blank>
Methyl groups
attachment of methyl groups (in cytosine) by the DNA transferase machinery to bases of the DNA which significantly influences GENE EXPRESSION and CELL FUNCTION
DNA Methylation
causes a blockage for binding of transcription factors, silencing or inactivation of genes
Methyl groups or moities
<blank> is an INTERFACE between the dynamic environment and the static genome
</blank>
DNA Methylation (Szyf)
Methyl is added by <blank> in methyl transferase in the Cytosine of 5' - CG - 3' dinucleotides</blank>
methyl transferase
TRUE or FALSE: High frequency of METHYLATED CpG islands within or in the vicinity of a gene’s promoter region REDUCES transcriptional activity of that gene
TRUE
<blank> accounts for the very specific patter of activating and silencing genes in every cell
</blank>
Methylation
<blank> genes are less methylated (also evident pattern in EARLIEST ZYGOTIC STAGES)
</blank>
Active
<blank? genes are inactivated (also evident pattern in EARLIEST ZYGOTIC STAGES)
hypermethylated
TRUE OR FALSE: Methylation may not be inherited per se
TRUE
TRUE or FALSE: Patterns are generated during gestation in accord with the signals from the environment
TRUE
TRUE or FALSE: Mistakes in methylation do not cause the same effect as a mutated gene
FALSE: causes the same effect
expression of <blank> depends on the ORIGIN OF INHERITANCE whether derived maternally or paternally.</blank>
Imprinted genes
TRUE or FALSE: There are cases when only maternal alleles of the imprinted genes are transcribed and the paternal alleles are silenced (VICE VERSA)
TRUE
TRUE or FALSE Epigenetic modifications cannot be passed across generations
FALSE: may be passed (Kaati, Bygren, and Edvinsson)
There is a “memory” of environmental influence on the genome
WHICH MECHANISM
Genetically identical mice may have different phenotypes (Agouti viable yellow gene causing yellow fur color, tendency to become obese, develop tumors)
The methylated agouti gene has a brown fur color and is healthy
DNA Methylation
Heavy methylation suppresses the expression of trait as observed in identical twin mice
TRUE or FALSE: Maternal diet can be affected by the environment
TRUE
TRUE or FALSE: Epigenetic factors other than foods, drugs, and environmental chemicals cannot change a developing organism’s expression
FALSE
“Superman” gene
Arabidopsis thaliana (Jacobsen & Meyerowitz)
(DNA Methylation)
Floral development is regulated by <blank></blank>
homeotic genes
(DNA Methylation)
encodes for a transcription factor that affects one of these homeotic genes
“Superman” gene
(DNA Methylation)
(2)
It controls the boundary between reproductive and accessory plant structures specifically <blank> to develop into carpels</blank>
“Superman” gene
fourth whorl of A. thaliana flowers
(DNA Methylation)
<blank> in the superman gene, just after the promoter region, causes variation in the formation of STAMEN and the CARPEL
</blank>
Cytosine methylation
(DNA Methylation)
‘superman’ gene bring about the <blank> and restricts the effect of another gene (APETALA 3)</blank>
clk allele (‘Clark Kent’ gene)
(DNA Methylation)
endemic to Mendoza province, Argentina
S. ruiz-lealii (shows recurrent flower malformations in its inflorescence within the same plant)
hypermethylation in S. ruiz-lealii
(DNA Methylation)
DNA associates with <blank> of histones</blank>
Octamer
<blank> modification can either support or suppress genes
</blank>
Histone
The tighter the association of histone tails to the DNA, the <blank></blank>
less accessible the DNA is for DNA PROCESSING and TRANSCRIPTION (or gene is silenced)
(HISTONE MODIFICATION)
Addition of methyl groups to histone tail =
restriction (tighter wound)
(HISTONE MODIFICATION)
TRUE or FALSE: Transcription factors can readily bind to genome promoters
FALSE: cannot
(HISTONE MODIFICATION)
Acetylation of histones
relaxes and unravels compact DNA (genes are more available as chromatin is more exposed and accessible to DNA binding proteins)
(HISTONE MODIFICATION)
combination of signals (causing methylate/demethylate, acetylate/deacetylate) =
lead towards modification of histones
(HISTONE MODIFICATION)
TRUE or FALSE: The area within nucleus where the modifications reside could convey information
TRUE
(HISTONE MODIFICATION)
TRUE or FALSE: Methylated DNA and acetylated histones are found in same components or territories in the nucleus
FALSE: different*
(HISTONE MODIFICATION)
TRUE or FALSE: Methylated DNA is associated with acetylated histones (vice versa)
FALSE: Methylated DNA recruits proteins that cause deacetylation of histones, resulting to shutdown of gene
(HISTONE MODIFICATION)
Third mechanism of epigenetic change which can silence a gene is <blank></blank>
RNA interference (RNAi)
RNA interference discoverers
Andrew Z. FIRE & Craig C. MELLO
can regulate the stability of mRNA and can be used to silence the expression of TARGET GENES
Short (21-25bp in length), double-stranded non-coding RNA (dsRNA)
or small interfering RNA
used for RNAi. Both pairs with specific target mRNA, causing inhibition of translation or degradation of mRNA
short, single stranded RNAs or microRNA (miRNA)
and short interfering RNAs (siRNA)