PCOL 838 Exam 1 With Questions And 100% ALL SURE ANSWERS
Terms in this set (149)
gene a segment of dna that encodes a pdt responsible for a measurable trait
locus location of a gene on a chromosome
allele a variant form of a gene
a biochemical event such as a nucleotide change, deletion, or insertion that has produced a
mutation
new allele.
heterozygosity Having two alleles at the same locus that are diff erent.
A term referring to the presence of only one allele at a locus, either because the other allele is
Hemizygosity
deleted or because it is normally not present, e.g., X-linked genes in males.
polymorphism an allele present in 1% or more of a population;
any characteristic that can be measured, with the type of measurement depending on the
phenotype
characteristic.
PCOL 838 Exam 1
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, 10/15/24, 2:15 AM
penetrance: manifestation of disease phenotype under a set of predefined criteria (% of
people who inherit mutation and express associated trait)
how can 2 individuals w/ the same mutation have
Incomplete penetrance of dominantly inherited disease- why deleterious allele persist in
the different severity of disease
population
- Same mutation can affect different tissues-> different phenotype-> variable expressivity
Explain the pathophysiologic difference between
mutations that act via loss of function and those
that
act via dominant negative gene action
autosomal, classical Mendelian inheritance, only one allele is working, gives rise to only 50%
Recessive loss of function mutation
protein level, need both alleles to manifest disease phenotype-> recessive inheritance
50% protein level= not enough for normal function->dominance inheritance. most are
Dominant loss of function mutation
semidominant w both loss of function alleles manifesting more severe phenotype
Involved in genes encoding proteins involved in
oligomeric or polymeric protein complexes
Dominant Negative Gene action
Mutant protein disrupts the formation of normal
protein complexes->inhibiting normal function=dominant inheritance
- depending on locus of mutated gene. Autosomal vs X-linked. Autosomal recessive or
Dominant. X- linked dominant fragile X syndrome) or recessive (hemophilia) mostly manifests in
What are the different mode of inheritance
men bec of hemizygosity. Codominance. Maternal inheritance or matroclinous inheritance in
mitochondria.
Mutations in genes located in the mitochondria DNA.
•
Lead to optic cell death and progressive vision loss.
•
Incomplete penetrance: 50% of male and 85% of
Leber hereditary optic neuropathy
female never experience any vision loss of related
(LHON
health problems.
•
Affected individuals are typically homoplasmy,
heteroplasmy individual will eventually become
homoplasmy
PCOL 838 Exam 1
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