Lecture 7 - Unusual Patterns of Inheritance Flashcards
the _____ region is the segment of the X and y chromosomes located at the most distal portion of their respective p and q arms. crossing over can occur during ____ meiosis
pseudoautosomal (PAR),
male
ie X and Y recombination
pseudoautosomal traits can have ___ to ____ transmission. the pseudoautosomal region of the X chromosome (is or is not) inactivated on the lyonized X in females
male to male;
is not
the PAR contains the ____ ____ homeobox containing gene. need (one or 2) copies for normal stature?
short stature;
2
so if only 1 copy–>short stature (turner)
pseudoautosomal _____ is a dominantly inherited skeletal defect with disproportionate short stature and deformity of the ____, due to mutation of short stature homeobox.
dyschondrosteosis;
forearm
what is another gene that can undergo pseudoautosomal inheritance?
SRY/testis determining factor
presence of the SRY gene on an X chromosome would cause a XX person to be phenotypically ___. the SRY gene causes production of what?
male (and infertile);
testis determining factor
in ____an offspring receives 2 copies of a chromosome from one parent and no copies from the other parent
uniparental disomy (UPD)
UPD:
heterodisomy (heterozygous) indicates a _____ error. Isodisomy (homozygous) indicates a ____ error or a postzygotic chromosomal ____ of one pair of chromosomes and ____ of the original pair.
meiosis 1;
meisos 2;
duplication;
loss
UPD:
we often the presume the fetus was originally ___ followed by ____ of a chromosome aka ____ _____
trisomic;
loss;
trisomic rescue
genomic imprinting (GI) = differential expression of alleles of a gene in ___ cells. involves a form of gene marking that is (reversible or irreversible?) ie _____ turns an allele off
somatic;
reversible;
hypermethylation
is a normal process
2 diseases with genomic imprinting problems?
what chromosome are these associated with
prader-willi,
angelman;
both on chrom 15
2 reproductive disease than may be caused by imprinting
complete hydatidiform mole;
ovarian teratoma
complete hydatidiform mole = ____ genomes only;
ovarian teratoma = ____ genomes only
paternal, maternal
prader willi syndrome (PWS):
the ____ imprinted gene is normally silent. the ____ gene is mutated or deleted
maternal;
Paternal (P for PWS)
PWS symptoms:
hyper____, ____, intellectual disability or no?;
____ gonads; ___tonia
phagia, obesity, intellectual disability (moderate);
small, hypo
also short stature
25% of cases of PWS are caused by ____ ___ _____
maternal uniparental disomy (ie both chromes from mom)
angelman syndrome (AMS): the \_\_\_\_ imprinted gene is normally silent. the \_\_\_\_ gene is mutated or deleted
paternal;
maternal (Maternal for Man)
AMS:
aka “____ ____” syndrome. inappropriate ____, intellectual disability or no?;
sizures, ataxia
happy puppet;
laughter;
yes (severe)
AMS:
5% cases due to ____ ____ ____;
other cases are due to mutation in UBE3A, which codes for ______
parental uniparental disomy (ie both chromes from dad);
ubiquitin-protein ligase
AMS:
UBE3A is usually only expressed in the ____ (ie tissue specific)
brain
imprinting:
occurs before or after fertilization?
must be ____ and is (reversible or irreversible) on passage through the opposite sex
before;
erased, reversible
ie male sperm doesn’t pass maternally imprinted chrome to male gametes (See ppt)
mitochondria DNA:
lacks ____ and ____ = increased mutation rate;
inheritance is ____;
DNA is ____
proofreading, DNA-repair;
MATERNAL;
circular
mitochondrial myopathies:
usually disorders of ____;
present with myopathy, ____ ____, and ___ probs
Oxidative phosphorylation;
lactic acidosis, CNS
_____ is the presence of both normal and mutated mtDNA in a cell, resulting in _____ expression of disease
heteroplasmy;
variable
homoplasmy is when you get all of same kind of mtDNA in a cell
____ ____ means that MtDNA is sorted randomly and mitochonria also distribute randomly
replicative segregation
the ____ ____: impact of mutation varies depending on the tissue, the timing, and the number of mutant mitochondrial per cell
threshold effect
____ ____ = number of mtDNA is reduced then amplified in the mature oocyte
genetic bottleneck
“ragged red fibers” are often seen in what mitochondrial disorder?
this is due to to decreased charged ___ = increased ____ _____
Myoclonic epilepsy with ragged red fibers = MERRF;
tRNA;
chain termination
MERRF causes myopathy, ____ seizures, ____ (CNS thing), and ____ (sensory thing)
myoclonic;
dementia;
deafness
