Notatki Danniego part 8 Flashcards
What can change H.W?
4) Negative assortative mating (unlike for like)
- Hermaphrodite flowers
-> may not self fertile a x ab fails
-> self incompatibility mechanism -> b x ab fails
c x ab succeeds
-> plant with d is advantageous as can mate with any of the others
-> but will they become more prevalant (?) and become less advantageous
-> anti-inbreeding mechanism
Mice
- female mouse will terminate a pregnancy and absorb the foetus from a male mouse that has same antigen and she smells the scent of a male from another lineage
- > ensures genetic diversity
Odorant receptor
- single largest gene family
- > 1/6 genes are to do with scent in humans
- > most are matured (?) oral have no effect now
Hutterites
- another religous-wolate group
- higher chance for couplers to marry people that were less (genetically) like them
- spontaneous abortion prevelant in women that had babies with genetically similar males
- > possible anti-inbreeding mechanism
What can change H.W?
5) Mutation
There is always input from mutation
What can change H.W?
6) Natural selection
frequencies before selection:
AA Aa aa Total freq a
Gen 0 p^2 2pq q^2 1 q
Assume aa is lethal:
sel. value l l 0
p^2 2pq 0
p^2 + 2pq = p( p+2q) = p( 1+q)
since p + q = 1 =>/
AA Aa aa Rel freq p^2/(p(1+q)) 2pq/(p(1+q)) 0 after selection
= p/(1+q) 2q/(1+q) ->
-> so that a= q/(1+q)
- The more common the lethal allele, the faster it is removed from the population
- > It is in heterozygotes
Mutagens include
- atomic bomb
- types of meat? (?)
- cigarettes take 20 years to show mutagenic effects. Some can take a long time to show
- even bacteria can be a mutagen
- > helicobacter pyroli infects lower par of stomach (antrum) causing peptic ulcar disease (?) - some genes predispose to somatic mutation
- > BRCAI -? breast cancer gene - old age
- > linked to mutations
- > maybe mutations cause old age
Hugo de Vries
Dutch geneticist
- worked on Oenothera lamarckiana (?) red(?)/white flowers, wrinkled/smooth flowers
- very variable plant
- realised change was due to mutations - made the name
- these plants shatter (?) and rejoin their chromosomes
C-14 dating average age of human body cell - … ……
- skin cells - …. ….
- RBC - … …..
Brain/heart/liver …….
- 10 years
- 2 weeks
- 4 months
very slow replacement
Cells that replace quickly are more likely to have mutations and cause cancer
->….
heart cell is very rare
Early somatic mutation leads to more cells showing the mutated characteristic as more cells grow from mutated one by mitosis
.
Proteus syndrome -
bare one growth from somatic mutation
Drosophila mutation
loss/gain of functions
-> loss of red pigment
/ -> extra thorax - 2 extra wings
/ -> legs replace anernae (?)
L-> homeotic mutantsLoss of function mutation tends to be recessive
-> first few generation of mutants will not show phenotype as hidden in heterozygotes
Deteering bacterial mutations:
1) Bacteria spread on original plate
2) Grows into colonies
3) Stamped onto penicillin - containing place using helmet pad (?)
4) Only resistant colonies survived with new mutation
- This experiment showed that mutations were spontaneous - not caused by the penicillin
Mutations in Maize
- Every corn normal is a seed
-> Endosperm
-> Triploid - 2 female + 1 male
CC x cc
Purple white
should be Ccc - all purple
The presence of a white normal shows mutation
Mutations in Mice
aa bb cc ++ ++ X ++ ++ ++ dd ee
f1: all a+ b+ c+ d+ e+
If mutation at locus C
a+ b+ cc d+ e+
= mouse with cc coat colour
- Used to test effect of mutagens today
- Can find patches of mutant coat colour on mice
Work on mutation rates by looking at (?) pedigrees and working out number of new mutations
~ 60 new mutations in every child from parents
Direct detection mutations in a tumour using FISH
.
Genetic heterogeneity - polydactyl
- > extra fingers
- > most similar looking mu(?) but don’t count
Phoemela (?)
- cleft hand mutation
- environmentally induced
- Phenocopy - copies a genetic mutation
Barbara Malintock -
- Showed particular genes that were harmless in one line, caused mutations in another line
f2:
9/16 A- D- black; D+ has no effect on A
3/16 A- dd black
3/16 aa D- dotted: D+ allele mutates a
1/16 aa dd white
-Dotted locus was moving around
Genomic instability - damages other genes
-> intrinsic
Variation in per-base (?) mutation rates
Higher rate in bigger genomes
Higher Eukaryotes - 10^-11 - 10^-9
Prokaryotes 10^-10 - 10^-8
RNA virus 10^-5 - 10^-4
Up to 500,000 DNA modification per day
-> We have repair enzymes to fix these
Warner Syndrome
promature ageing due to DNA repair failure
more common in Asia
Ionising radiation:
UV, X-Ray, Gamma
