Which type of genetic condition is Cri-Du-Chat syndrome?
Cri-du-chat results from deletion error in the chromosome. 5p- specifically
Cri-Du-Chat presentation
Cri-du-chat (cat's cry) syndrome, also known as 5p- (5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. Affected individuals also have distinctive facial features, including widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face. Some children with cri-du-chat syndrome are born with a heart defect.
What type of disorders are usually associated with repeat expansions (STRs, VTRs)?
Neurological disorders. Think perseveration.
Anticipation in context of repeat expansions
anticipation is the progressive increase in genetic problems in future generations.
if grandpa died at 60, dad died at 50 and son died at 40, what might this be an example of?
anticipation in genetic problem
STR
Short tandem repeat
VTR
variable number tandem repeat
STR vs VTR
Both are repetitive sequences of DNA, usually found in the non-coding section of a gene, VTRs are longer
CNV vs STR/VTR
Copy number variants, much larger and may duplicate whole genes and genetic segments
cause of structural abnormalities in cells
mutant cell lines in the early developing embryo
paracentric mutation
dna re-inserted without the centromere
pericentric mutations
reinserted piece of dna with the centromere
isochrome mutation
mutation ending with two p-arms or two q-arms
autosomal aneuploidy
abnormalities not involving the sex chromosomes
Trisomy 21
Chromosomes 1-22 are autosomal
Chromosome 23 is
sex chromosome
Chromosome 23 is the sex chromosome
Chromosomes 1-22 are
autosomal
Examples of conditions from sex chromosome aneuploidy are:
Turner syndrome (X0, missing second X chromosome)
Kleinfelter
syndrome (XXY, extra X chromosome)
Turner syndrome
...
Klinefelter syndrome
...
Polyploidy
More than two paired sets of chromosomes
Example of polyploidy
Triploidy, involves 69 chromosomes, leads to abortion
Nondisjunction
Refers to the failrue of homologous chromosomes to separate properly during cell division
When can nondisjunction happen?
During meiosis I or II separation does not happen properly and the gamete has abnormal chromosome numbers
Pyramidine bases
CUT
Purine bases
AG
AUG
Start codone, Methionine
UAA
UGA
UAG
You are annoying
You go away
You are gone
Stop codons
Prophase II
Spindles show up from the centrosome and get ready to pull chromosomes apart
What is the function of mRNA
This carries the transcribed copy of a protein code to the ribosome in the cytoplasm where translation can occur and proteins can be synthesized.
What are codons?
3-nucleotide sequences within the mRNA that specify for particular amino acids
3 categories of genetic/genomic diseases
Chromosomal disorders
Single gene defects
Multifactorial
diseases with complex inheritance
What is the process by which mRNA is created
RNA Polymerase converts the gene into mRNA
Characteristics of the genome:
Chromosomes
Genes
DNA
Genome- all of it
chromosomes- 46 of em (23 pairs)
genes-
20-25k
DNA- sequences of nitrogenous base pairs
Prometaphase
In between prophase and metaphase
Spindle fibers that showed up
attach to chromosomes
Process of transcription
RNA polymerase copies DNA in chunks
Translation
The process of translating the RNA into functional proteins
S phase of cell cycle
This is where chromosomes are synthesized, 96 chromosomes in the cell at this poiint
Codominance
AB blood type, both are dominant so you get both
Also, spotted cow
Incomplete dominance
Red flower + white flower = pink flower
rRNA's role is
rRNA is a non-coding RNA which is the primary component of the ribosome and carries out protein synthesis in ribosomes.
G0 phase
Cell is resting, 0 growth at this phase = G0
Telophase
Chromosomes make it to the opposite end,
new nucleus forms
around the chromosomes
actin fibers pinch the middle and start to
divide the cell
tRNA
Link that carries 3 nucleotides to the ribosome for protein synthesis
Anaphase
Fibers shorten and pull the sister chromatids apart, to the opposite end of the cell
Regulatory sequence in DNA
Site of the binding of regulatory proteins that allow for more or less expression of genes
FISH (Fluorescense In-Situ Hybridization) tests
chromosomes
Predisposition genetic testing
Testing for asymptomatic people who are at <100% risk of genetic problem
Presymptomatic testing
Testing of asymptomatic people who are at 100% risk of genetic problem (Huntingtons that hasnt begun yet)
Diagnosis and prognosis of leukemia. What are you testing?
Philadephia chromosome - translocation (trading of section) of chromosomes 9 and 12
Genomic defects: BRCA 1/2
Potential to cause hereditary breast and ovarian cancer
X linked inheritance with an affected mother and unaffected father
50/50 affected, because it is dominant, no carrier. You either get it or you dont.
Carrier mother - O
Unaffected father (square)
2 unaffected,
1 carrier daughter, 1 affected son
X linked recessive
Unaffected father
Affected mother
2 affected sons, 2
carrier daughters
X linked recessive
Females can be carriers but men cannot
Abnormal allele occurs in
equal frequency in males and females
Males always exhibit trait
are are more commonly affected
Females require both abnormal alleles
X linked recessive
Hemophilia A
Duchennes muscular dystrophy
Red-green color blindness
X- recessive
Affected father, unaffected mother
2 unaffected sons, 2 carrier daughters
X recessive
Y linked inheritance
Only males are affected
Affected males pass to all
sons
Females are not affected and not carriers
Females do
not pass on
When using methylation for genetic testing, what are you testing?
Epigenetics
DNA sequencing is also called
Next generation sequencing
Autosomal dominant example
Huntington
hunters are dominant as fuck
Autosomal recessive examples
taysachs
cystic fibrosis
Autosomal recessive affected parents
Will always have affected offspring
Carriers only apply to:
Recessive