Huntington's Disease

• Late onset (40s)
• Dominate
• Neurodegenerative disorder casued by death of nerve cells
• DEATH
• depression, involuntar jerky motions
• 1:10,000

• gene product: Huntingtin with long poly-glutine stretches
• funtion of protein isn't known
• the stretch of glutamine gets too long and the long protein kills the cell
• easil diagnosed by Polymerase chain reaction

• the product of two or more INDEPENDENT EVENTS is the product of the proability of the events itself
• the probability of  getting heads two times in a row (.5x.5=.25)
• probability of having three girls in a row (.5x.5x.5=.125)

• the probability of either of two MUTALLY EXCLUSIVE events occuring is the sum of their indivudual probabilites
• Happens at the same time
• offspring will be a boy or a girl, heads or tails (.5+.5=1)

• [image]
• Many fingers
• variable expressivity- shows up differently, different size fingers
• Dominant Disorder

• midgets
• dominate disorder
• AA=DEAD!! Lethal Dominate disorder
• proability of having normal kids is 1/3

• most common RECESSIVE disorder
• 1:3,500
• 12 million carriers
• 33 years life expectancy
• no cure but gene therapy efforts underway

• mucus clogs airways
• Caused by defective ion channel
• The ion channel that moves Cl out of cell isn't there
• since the Cl can't be moved, it throws off osmtic pressure

• Same disease can be caused by lots of different traits
• Albanism (recesive)

• a trait that becomes broader and adds variety as it is passed down through generations
• SKIN COLOR

• no particular trait is dominant over another
• Red + White flowers = pink!
• phenotype is inbetween but neither is clearly displayed

Why Were pea plants good for Medel?

(3 reasons)

1. discrete traits (vs. continuous) the traits stayed the same over generations. Pure breeding- the purple flowers only made purlple, not other lighter or darker shades.
2. fertilization control - he picked what reproduced
3. large progeny (statistics)- he used actual numbers, which is good

• production of Wild-type progeny when recessive mutations in two different genes are combined
• AAbb and aaBB make albinos
• this is also how two albinos can have normal colored kids
• aaBB+AAbb= normal
• aaBB +aaBB =albino
• AAbb+AAbb= Also albino

• Both alleles are clearly expressed
• blood types
• AB = two dominant alleles being expressed in 1 person, have both A and B sugars

• Caused by a mutation in the blood called FUTI
• ii is the genotype
• there is no Substance H for the A or B sugars to attach to
• Bombay woman

• The expresson of one gene masks the expression of another
• homozygous hh is epistatic over any allele combination of i gene. (that's why we have an O blood type)
• Recessive epistasis-allele must have 2 copies
• Dominant- one is enough to show up

• most common disorder for african americans
• 1:625
• Caused by defective hemoglobin
• many effected dies as kids
• high number of S allele causing disease: confers resistance to malaria

• defective Beta Globin
• The butanic acid (+) is replaced by Valine (nonpolar)
• changes the solubility in H2O

• a mutation in ONE gene affects more than one trait
• Sickle cell- makes you more resistant to malria. Also affects how the blood is shaped at sea level vs. High altitudes
• Diseased people are effected more strongly at high altitudes
• Skin color

• Penetrance= percenatage of individuals with a given genotype who express that genotype at the phenotypic level.
• penetrance is incomplete if it is less than 100%

In humans and flies (drosophila):

XX is _____

XY is ______

XX= female

XY= Male

In true bugs (hemiptera):

XX is ____

XO is _____

XX is girls

XO is boys

caenorhabditis elegans (XX hermaphrodites)

In Birds, amphibians (xenopus), and butterflies:

ZW is _____

ZZ is _____

zw = females

zz = Boyzzzz

in some reptailes like the hawksbill sea turtle, zo is femal

• they turn one off
• Bar bodies (females) the turned off X chromosome

• 47 Chromosomes
• XXY
• Male but sterile, doesn't produce sperm
• 1:500

• Turner Syndrome

• 45,X
• female but no eggs
• 1:3000