9.9 Single Gene Inheritance 1 and 2 Flashcards
Tay-sachs disease is an example of what inheretence pattern?
autosomal recessive inheretence
in X-linked dominant inheretence, is a male is affected, what is the outcome of the daughter?
The daughters would definitely be affected. They inheret the X from their father.
autosomal dominance pattern of inheritance displays vertical inheritance, which means:
usually the phenotype appears in every generation
X-inactivation is a random event, so most females have the paternal X in ____ of their cells and maternal X in _____ of their cells. can this change?
half, half
yes, some females can have different proportions
neurofibromatosis shows _______ expression
variable
an all-or-none phenomenon. You either show features of the genotype or not at all. Even though they have the mutated gene, not everyone who has the gene gets the disease.
reduced penetrance
is there a gender bias in autosomal dominance pattern of inheritance?
no
in X-linked inheretence in general, can fathers pass on the disease to their sons?
NO
what type of inheretence pattern is this pedigree?
autosomal dominance pattern of inheritance
The position of a gene on a chromosome
locus
why do some females have milder or more severe phenotypes of X-linked diseases?
Lyon hypothesis - they have different proportion of active and in-active X-linked genes.
what pattern of inheretence is this?
autosomal recessive
in autosomal recessive inheretence, the parents of an affected individual are usually _______
unaffected
in X-linked recessive inheretence, an affected father will make all of his daughters what?
carriers. all of them recieve the x* from their dad
the finding that females express only one allele of their X-linked genes, although they actually have two. Ensures that females do not produce twice the gene product. What is this called?
dosage compensation
When mutant genes produce effects on multiple organ systems and functions.
plieotropy
in autosomal recessive inheretence, is there a gender bias?
no
BRCA1 mutation causes cancer in 80% of people with the genotype, while 20% of people with the genotype do not get cancer. what is this called?
reduced penetrance
individuals with the same geneotype have different phenotypes. Differences in location, size, number of neurofibromas for example in neurofibromatosis. Range of signs and symptoms.
variable expression
what can help explain variable expression in females?
the Lyon hypothesis
neurofibromatosis shows which type of inheretence?
autosomal dominance pattern of inheritance
1 allele at a locus
hemizygote
autosomal dominance pattern of inheritance does/doesn’t skip generations
doesn’t
in female somatic cells, _____ X-chromosome is active
one
Duchenne muscular dystrophy is an example of what type of inheretence?
X-linked recessive inheretence
Marfan syndrome affects many different organ systems of the body. What is this called?
pleiotropy
when abnormal phenotype is caused by mutations at 2 or more separate loci. Same condition caused by mutation of different genes
locus heterogeneity
when the abnormal phenotype is caused by different mutations at the same gene (same locus)
allelic hetergeneity
Alternative forms of the gene found at the same locus on homologous chromosomes.
allele
what type of inheretence pattern is this?
x-linked dominant
in female somatic cells, one X-chromosome is ______ and one is condensed and represented as the ____________
active
Barr body
the BRCA1 mutation shows what type of inheretence?
autosomal dominance pattern of inheritance
what type of genetic inheretence exhibits horizontal inheretence? what does this mean?
autosomal recessive inheretence
it means that affected individuals are usuallly seen in one sibship
in autosomal dominance pattern of inheritance, _____ affected people have an affected parent
all
Hemophilia A is an example of what pattern of inheretence?
X-linked recessive inheretence
Marfan syndrome shows what pattern of inheretence?
autosomal dominance pattern of inheritance
in autosomal dominance pattern of inheritance, _______ of the offspring of affected parents are affected
half
Tay-sachs disease is an example of a disease concentrated in ____________, such as the Ashkenazi jews
genetic isolates
what pattern of inheretence is this?
x-linked recessive
