Principles of Genetic Inheritance Flashcards
Chromosomes common in both genders
Autosomes
This disease is a mitochondrial disease that affects many body systems, particularly brain and nervous system, and muscles.
– Stroke and dementia – Lactic acidosis
Mitochondrial encephalomyopathy, lactic acidosis, and
stroke-like episodes (MELAS)
Example of X-linked Recessive Disease.
Duchenne Muscular Dysterophy
Turner Syndrome Characteristics
45, XO karyotype
Female (no Y)
Short stature
Ovarian hypofunction/premature Ovarian failure- require hormone therapy
Most are infertile
~30% webbed neck
Low hairline on neck
CV defects (coarctation of aorta, bicuspid aortic valve)
Normal intelligence
Is pyloric stenosis more common in men or women?
Men, they need less risk genes.
Children born of affected males are less likely to get it as well.
Probabilty rules
Multiply individual probabilities for “and”
Add for “or”
When environmental factors cause variation
in the trait, the term ______ is used
Multifactorial
Process by which monosomy and trisomy occur.
Non-Disjunction
Meiosis reduces the total number of chromosomes by ___ producing ____ number of haploid gametes
1/2, 4
Order and nomenclature is divided into how many sections
Arm P / Q
Region 2 / 1
Band 1,2,2 / 1,2,3,4
Subbands 321,21,54321 / 3,123,1234.123
Describe the structure of mitochondrial DNA
16,569 bp, double stranded, circular
The frequency at which a gene manifest itself is called _____.
penetrance
Klinefelter Syndrom Characteristics
– Some with no/limited symptoms
– Varying degrees of cognitive, social,behavioral, learning difficulties
– Primary hypogonadism (low T)
– Small and/or undescended testes
– Gynecomastia
– Tall stature
– Infertility
– Can be mosaic
– Variability in X numbers can increase
symptoms (48, XXXY; 49, XXXXY)
47, XXY
Name the phases in order for mitosis
Interphase
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
Phase of Mitosis at which one copy of each chromosome (chromatid) and 1/2 of cytoplasm/organelles are distributed between the two daughter cells
Cell Division
Law of Independent assortment in Mendelian Genetics
Genes are inherited independently of one another
What is Trisomy 21?
Downs syndrom (47, XX + 21)
Most common trisomy
Inreased risk with maternal age
Can also occur due to translocation 46, CU
Multifactoral diseases that due not show a phenotypic bell curve have an underlying ________. In order for disease to become present they must pass the _________.
Liability distribution
Threshold of liability
X-Linked Dominant Disease
Very rare; No carriers
Hyophosphatemia
Low phosphorus in blood due to defective reabsorption of phosphate in kidney due
Deficient absorption of calcium in intestine causing sofenting of bone (Rickets)
Vitamin D metabolism abnormal
Short stature
How are genomic imprints passed down?
They’re not!
Epigenetic imprints remain throughout the lifespan of somatic cells.
In germ cells, epigentic imprints are reset at each generation.
Normal number of chromosomes
Euploid
Paternal deletion of region of chromosome 15
Prader Willie Syndrome
Short stature, hypotonia, small
hands/feet, obesity, mild to moderate
intellectual disability
What makes multifactoral inheretance recurrent risk more likely?
Environmental factors
More then one family member affected
Expression is more severe
Less commonly affect proband is more likely to pass on
More related the parents = Higher chance
Disease example given for Reduced penetrance
Retinoblastoma
autosomal dominant inheritance
Phenotype occurs in 90% of individuals inheriting gene
