● Angelman syndrome: paternal imprinting
○ Chromosome that came from father is silenced
○ If mutation inherited from mother, there is no functional copy in the child because
father’s allele is silenced
● UBE3A-ATS (antisense) RNA is expressed near promoter
○ Long non coding RNA
○ Transcript binds mRNA of UBE3A gene
○ Oligonucleotides can silence the ATS (silencer) to unsilence the paternal copy
and express the UBE3A
● Allelic heterogeneity: multiple mutant alleles in one gene
○ Ex: CFTR gene in CF
● Telomeres: helps protect tips of chromosomes
○ The shorter the telomere, there is more danger to the chromosomes
■ Ex: those who have more stress have shorter telomeres
● Telomerase lengthens telomeres and prevents chromosome shortening
● Not all somatic cells express telomerase and have unlimited division because it can lead
to the formation of tumors
● Chromatin is made up of ⅓ DNA, ⅓ histones, and ⅓ nonhistone proteins
○ Histones are positively charged and DNA is negatively charged so histones and
DNA have a strong attraction to each other
● Karyotypes are examined by high resolution G banding
● FISH: Fluorescence in situ (in the tissue) Hybridization
○ Specific probes, an oligomer, are designed to test where a specific gene is located
on the chromosome
● Telomeres can be a marker to show something is wrong
○ Chromosome that came from father is silenced
○ If mutation inherited from mother, there is no functional copy in the child because
father’s allele is silenced
● UBE3A-ATS (antisense) RNA is expressed near promoter
○ Long non coding RNA
○ Transcript binds mRNA of UBE3A gene
○ Oligonucleotides can silence the ATS (silencer) to unsilence the paternal copy
and express the UBE3A
● Allelic heterogeneity: multiple mutant alleles in one gene
○ Ex: CFTR gene in CF
● Telomeres: helps protect tips of chromosomes
○ The shorter the telomere, there is more danger to the chromosomes
■ Ex: those who have more stress have shorter telomeres
● Telomerase lengthens telomeres and prevents chromosome shortening
● Not all somatic cells express telomerase and have unlimited division because it can lead
to the formation of tumors
● Chromatin is made up of ⅓ DNA, ⅓ histones, and ⅓ nonhistone proteins
○ Histones are positively charged and DNA is negatively charged so histones and
DNA have a strong attraction to each other
● Karyotypes are examined by high resolution G banding
● FISH: Fluorescence in situ (in the tissue) Hybridization
○ Specific probes, an oligomer, are designed to test where a specific gene is located
on the chromosome
● Telomeres can be a marker to show something is wrong
