Genetic Diseases 2 Flashcards
Foxglove purple/white petals
2 loci involved, hmz at either = white; htz at both=purple
Complementation
-> 2 different hmz recessive mutations produce same phenotype
Human Deafness
Many loci affect hearing pathway - from outer ear to aud nerve and brain
Complementation
Colour Blindness
X-linked - (daltonism)
Lesch-Nyhan syndrome
Error in purine metabolism - self-mutilation, death
X-linked
Haemophilia
Factor VIII deficiency - blood can’t clot properly
X-linked
mutation probably happened in Queen Victoria’s father - who was old
Duchenne muscular dystrophy (DMD)
Detect age 3-5, fatal in 20s
X-linked/ X-chromosome inactivation
one remarkable case of MZtwins, each had inactivated a different X chromosome, 1 had DMD, 1 did not
Tortoiseshell cat
Patches of black and orange fur (black activ 1 X chr, orange the other)
X chr inactivation, XCI
Colourblindness in women
woman htz: some retinal cells normal, some colour-blind
X chr inactivation, XCI
htz woman can see even though some retinal cells are abnormal
Patau syndrome
Trisomy 13
chromosomal abnormality
Notch Wing
in Drosophila melanogaster
- chr deletion
Cri-du-chat
lose tip of chr 5
- chr deletion
- child voice sounds like cat
Globin, odorant-receptor gene families
chr duplication
increase genetic material progressively, then changes, get new but similar genes : families
Dm Bar eye
Bigger eye
- chr duplication
if cross 2 Bar eye: sometimes get double Bar eye + normal eye – due to slippage
Myeloid leukemia
Translocation 5-11/ 9-22
- > myeloid line of blood
- > abnormal WBC in bone marrow
Burkitt’s lymphoma
Translocation 8-14
-> B cells + impaired immunity
Down’s syndrome
trisomy 21 / translocation 14-21
Aneuploidy
early aging, excess water in uterus - flat face, fingerprints
Edward’s syndrome
trisomy 18
Aneuploidy
lethal - kidney, heart abnorm (sth w clenched fingers)
Klinefelter’s syndrome
XXY, XYY male // XXX female
Aneuploidy
XXY is male but has some female characteristics - sometimes dont notice till fertility tests
Turner’s syndrome
XO, female
Aneuploidy
If females normally have 1 inactivated, should be normal, right ?NO - heart stuff, diabetes,
Gynandromorphs
Half male half female - mosaic (due to error in mitosis in early dvp)
Somatic Aneuploidy
Dm one red eye one white
Modern wheat
is hexaploid
Allopolyploid
-triticale is another allopolyploid
banana, ginger, seedless melon
infertile triploids
¿? autopolyploid (modern manipulation)
Siamese cats
Fur colour det by mut in melanin gene - enzyme doesnt work at high temp
Temperature-sensitive mutations
-cooler parts of body ie ears/paws are dark cause cooler temp in extremities
White-blood in Dm
high temp light eyes/low temp dark eyes
Temperature-sensitive mutations
-use to study temp-sensitive period of dvp
- correlated w/ mutation in eye cryptochrome gene
- gene-env interaction
phenylketonuria, PKU
absent Phenylalanine hydroxylase, PAH
- gene-env interaction, chemical
- recessive
- can’t break down Phe -> special diet
porphyria variegata
Defict in some enzyme - cant break down porphyin component of haemoglobin, it accumulates (light sensitive chemical)
- gene-env interaction, chemical
- inc pen __rec/dom
- neurolog sympt, light sensitivity, low doses of barbiturates lethal - maybe gave origin to werewolf legend // George III
factor V leiden thrombophilia
Disorder of blood clotting
incomplete penetrance, gene-env interaction, chemical
- dominant
Baldness
gene-env interaction, sex limitation
- dominant
