Week 3 Mutations-P2 Flashcards
Cytogenetics
The study of chromosomes and their abnormalities
The goal of cytogenetic analysis
To help diagnose / plan treatment,
Meta centric, sub centric and acrocentric
M-Centre
S-Slightly off set
A-At the edges
Euploidy
Having correct no of chromosomes
Polyploidy
Presence of abnormal amount of chromsomes e.g 2-3-4 more
Aneuploidy
Missing or having an extra
non-disjunction
Failure for chromosomes to split apart and go into new daughter cells
Condiitons examples and chromosomes group involved
Downs 21
Edwards 18
Patua 13
How can chromosomal mutations occur
deletions, inversions, translocations
Name and explain the two types of chromosomal deletion
Terminal deletion - Single break, loss of the tip
Interstital deletion - Two breaks, loss of material
Chromosome inversion
Two breaks of chromosome, inverts and moves into other pair
Translocation
A portion of one chromosome is transported to the other
Reciprocal translocation
exchange of segments between non-homologous chromosomes
Robertsonian translocation
the long arms of two non-homologous, acrocentric chromosomes
fuse at the centromeres to form a single chromosome
How do cancer cells arise
Genetic mutations like oncogenes, tumour suppressor genes or DNA repair genes, loss of cell cycle control
Cancer cells prevent apoptosis
Molecules used in these phases
CDK’s - uses target protein to speed production
Tumour suppressor - Stops cell cycle if not correct
How does an oncogene arise
Point mutation - nucleotide change causes protein to become resistant to regulation e.g RAS mutation
Gene amplification - Multiple copies = over expression e.g HER2 in BC
Chromosomal translocation - One chromosome is transferred to another, fuses with adjacent protein, e.g BCR fusion in leukemia
