Cause of genetic mutations Flashcards
what is a germline mutation
sperm or egg already has the mutation. All cells of embryo are affected
what would the difference between an early somatic embryonic mutation and a late one be?
Early= more of the body affected
name and describe the 3 general types of mutations
genomic - loss or gain of whole chromosomes (eg trisomy)
Chromosomal - bits of chromosome are rearranged eg translocations
Gene - single or very few bases are substituted or otherwise changed
What is a point mutation?
change in a single base pair
what are the 4 potential consequences of point mutations
Silent
Nonsense (stupid name means unexpected TAG TAA TGA/UAG UAA UGA STOP codon)
Missense conservative
Missense non-conservative
what amino acid is too prevalent in sickle cell due to a point shift mutation?
Valine
what is the consequence of too much valine in the haemoglobin in sickle cell?
haemoglobin molecules crystallise when O2 levels are low in the blood. RBCs sickle and get stuck in the small blood vessels causing immense pain
Consequence of frameshift mutation?
From mutation to end of the sequence is incorrect.
what is the cause of Tay Sachs disease
8 frameshift mutations and 65 point mutations
how is Tay Sachs transmitted to the next generation
autosomal recessive
how does Tay Sachs disease manifest?
mutations in Hex-A gene, lysosomal storage disease. Increased gangliosides, becomes toxic. No cure. Most will die in infancy
which bit of which chromosome is deletd in Cri Du Chat
p arm of Chr 5
name a disease which is caused by chromosomal duplication
Charcot Marie Tooth p arm of 17 large region
what is XX male disorder?
SRY gene translocates from Y to X chromosome
what is Non-disjunction?
Chromosomes fail to separate properly at anaphase (usually in meiosis) so you can get one or three rather than 2 and 2
