Compiled from lecture notes, this is a condense but detailed summary of genomic imprinting covered in BHCS3009 module. All the information (and more) is available in one place in a logical order, easy to search and use for revision.
2nd main explanation for non-traditional inheritance (doesn’t fit expectations of Mendelian inheritance)
Genomic imprinting
• The process of gametogenesis in one sex marks some genetic material as being different from its
counterpart supplied by the opposite sex
• Imprinting suppresses action of the imprinted allele, so trait is suppressed – imprinted allele is not
expressed
• Early evidence of imprinting
o Mouse embryos
▪ Can use nuclear transplantation so both haploid chromosome complements in
embryo derived from same parent
▪ Embryos with maternally derived nucleus have poorly developed extra-embryonic
membranes, although embryos are normal
▪ Embryos with paternally derived nucleus have normal membranes but abnormal
embryos
▪ Both are non-viable for life – shoes important need for both paternal and maternal
pronucleus for normal development
▪ Imprinting during gametogenesis possible explanation
o Triploids
▪ Diandric triploids (2 male, 1 female genome) have large, abnormal placenta
▪ Digynic triploids (2 female, 1 male genome) have underdeveloped placentas but can
survive long enough to be studied
o Uniparental disomy (UPD) –
▪ Euploid (normal) genomes where both copies of one chromosome, or major portion
of chromosome, from each parent
▪ Believed to arise from non-disjunction in both parents (failure to separate at
anaphase)
▪ Gives rise to 2 copies of a chromosome in a gamete from one parent and no copies
of the chromosome from the other parent
▪ Can arise from translocation, where major parts of both chromosome derived from
same parent
▪ UPD from balanced translocations (in mice) helped to define which regions of
genome are susceptible to imprinting
▪ Types of UPD
Types of genomic imprinting
• Maternal imprinting – allele is NOT expressed when transmitted by mother (is expressed when
transmitted by father)
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller AH1984. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.42. You're not tied to anything after your purchase.
