Unit 3 Exam lecture 20 Flashcards
Phenotypes and processes transmitted to cells but not the result of genome sequence are called
epigenetic changes
Are epigenetics heritable
yes
Explain the process how newly synthesized DNA strands get methylated
After replication, half of double strand is methylated and half is unmethylated, methyl transferases add methyl groups to unmethylated strands
What is Dnmt3
active gene in female honey bees that stimulates methylation of genes for queen characteristics
What silences Dnmt3
royal jelly (siRNAs)
What happens early in development if a worker bee female is injected with siRNA that targets Dnmt3
those bees will become queens
royal jelly is an example of
an siRNA
What are the three ways that histones can be modified
methylation, acetylation and phosphorylation
Modification of histones are carried out by which proteins
polycomb protiens (PcG proteins)
PCR2 is what and does what
it is a PcG protein that adds two methyl groups to lysine 27 of H3
What happens when PcGs are mutated
they become non functional causing major developmental changes in phenotype
What do PcGs do
proteins which are responsible for the modification of histones
What is genomic imprinting
when one copy of a gene or group of genes is switched off
How can genetic diseases arise around genomic imprinting
One copy of a gene is silenced and the other active, if the active copy gets deleted then it can cause a genetic disease
Prada-Willi and Angelman syndroms are exampls of what
Genetic diseases due to deletion of non genomic imprinted copy of gene
the r1 locus in corn controls what
kernel color
Rr allele is for
purple kernels
the Rst allele is for
spotted kernels
RrRst codes for what colored kernels
spotted kernels
Subsequent Rr plants after being RrRst will produce which kernels and why
spotted kernels due to interaction of alleles that lead to heritable change in the Rr allele
What are the three characteristics of paramutation
- newly stablished expression pattern is transmitted to future generation even though the original allele is absent
- altered allele is now able to convert other alleles to new phenotype
- no associated DNA sequence different in altered alleles