inheritance and dna structure tbl Flashcards
know the symbols used in pedigree analysis look at ipad pic
whats the central dogma
dominant paradigm molecular biology dna - rna - polypeptide (proteins)
post translational changes to proteins even those that do not bind DNA can be heritable
epigenetics
by convention we describes polynucledotides in the ____ direction
5’ to 3’ direction
this is the direction of DNA and RNA synthesis
relaxed b dna
strands do not wrap around each other evenly, sugar phosphates “backbones” are far fapart 22 a grow closer 12 a
two categories that distinguish both compaction and accessibility of the chromatin DNA
heterochromatin and euchromatin
epigenetics
“marks” influence how the genome is interpreted
all changes that influence the phenotype without altering the genotype they consist of changes in the properties of a cell that do not represent a change in genetic information at the level of DNA sequence.
which of the following often results in the presence of uracil in dna
deamination of cytosine
the hardy weignberg equation is never met in humans ever
(p+q)2=p2+2pq+q2=1
its only true when theres large population with random mating that has genotype frequencies which remain constant from one generation to the next
why is hardy weinberg equation clinically relevant
allows us to estimate carrier frequencies and the disease incidence for autosomal recessive diseases this can be used for x linked disease
important concept is that carrier frequency is far more common than disease incidence and allele frequency
autosomal dominant 50% chance of passing allele from affected parent to child
examples huntington disease or marfan syndrome
autosomal recessive must inherit 2 copies of this allele 1 form each parent typically not in every generation
example
cystic fibrosis and sickle cell disease
2 carriers who are unaffected have 25% chance of passing this gene
they have 50% chance of child being carrier but unaffected and another 25% chance that they will no inherit the allele at all
x linked dominant women and men need only inherit one copy of the allele for it to be expressed
females may experience
less severe symptoms than males because of their other X chromosome. Fathers
cannot pass this on to their sons. exempli gratia Fragile X syndrome
MALES ONLY HAVE 1 X CHROMOSOME and thus if they
inherit a copy from their mother they will express the disease. FEMALES HAVE 2 X
Chromosomes and therefore almost never express these diseases.
x linked recessive
Fathers can pass this
gene onto their daughters but not their sons. exempli gratia hemophilia, and Fabry disease
