19 Genetics & Development 3 Flashcards
Interpret a pedigree chart: label the image
see image
Four Rules of the Pedigree chart:
1. AD =
2. If disorder is dominant what can be inferred about parents?
3. Recessive disorder - parents?
4. X-linked?
- AD = autosomal dominant // Disease appears in both sexes equally
- If disorder is dominant = one of the parents must have the disorder
- Recessive disorder - neither parent has to have disorder because both can be heterozygous
- X-linked - Allele located only on X chromosome = recessive by definition
Looking at a pedigree chart, how could you determine if a disorder is X-linked or autosomal?
- If most males in the pedigree are affected = X-linked
- If 1/2 ratio (50/50) between M and F = Autosomal
In the image is the disorder:
A. Autosomal Dominant
B. Autosomal Recessive
C. X-linked?
Autosomal recessive
Recessive disorder - neither parent has to have disorder because both can be heterozygous
In the image is the disorder:
A. Autosomal Dominant
B. Autosomal Recessive
C. X-linked?
Autosomal Dominant
AD = autosomal dominant // Disease appears in both sexes equally
2. If disorder is dominant = one of the parents must have the disorder
In the image is the disorder:
A. Autosomal Dominant
B. Autosomal Recessive
C. X-linked?
X-linked
Allele located only on X chromosome = recessive by definition
- generally recessive in females - affects males at higher rate
Differentiate between
- autosomal dominant
- autosomal recessive,
- X-linked,
- Y-linked and
- mitochondrial inheritance patterns
- autosomal dominant: manifested ikn the heterozygous state (at least one parent is usually affected) // affects both males and females
- autosomal recessive: both alleles at given locus are mutated // trait doesnt usually affect parents // 25% risk for each child
- X-linked: generally recessive in females - affects males at higher rate
- Y-linked - only affects males (father -> son)
- mitochondrial inheritance patterns: maternal inheritance (ova contain numberous mito. within abundant cytoplasm»_space; spermatozoa)
Differentiate between
- autosomal dominant
- autosomal recessive
- X-linked,
- Y-linked and
- mitochondrial inheritance patterns
- autosomal dominant: manifested ikn the heterozygous state (at least one parent is usually affected) // affects both males and females
- autosomal recessive: both alleles at given locus are mutated // trait doesnt usually affect parents // 25% risk for each child
- X-linked: generally recessive in females - affects males at higher rate
- Y-linked - only affects males (father -> son)
- mitochondrial inheritance patterns: maternal inheritance (ova contain numberous mito. within abundant cytoplasm»_space; spermatozoa)
Differentiate between
- autosomal dominant
- autosomal recessive
- X-linked,
- Y-linked and
- mitochondrial inheritance patterns
- autosomal dominant: manifested ikn the heterozygous state (at least one parent is usually affected) // affects both males and females
- autosomal recessive: both alleles at given locus are mutated // trait doesnt usually affect parents // 25% risk for each child
- X-linked: generally recessive in females - affects males at higher rate
- Y-linked - only affects males (father -> son)
- mitochondrial inheritance patterns: maternal inheritance (ova contain numberous mito. within abundant cytoplasm»_space; spermatozoa)
Differentiate between
- autosomal dominant
- autosomal recessive
- X-linked,
- Y-linked and
- mitochondrial inheritance patterns
- autosomal dominant: manifested ikn the heterozygous state (at least one parent is usually affected) // affects both males and females
- autosomal recessive: both alleles at given locus are mutated // trait doesnt usually affect parents // 25% risk for each child
- X-linked: generally recessive in females - affects males at higher rate
- Y-linked - only affects males (father -> son)
- mitochondrial inheritance patterns: maternal inheritance (ova contain numberous mito. within abundant cytoplasm»_space; spermatozoa)
Differentiate between
- autosomal dominant
- autosomal recessive
- X-linked,
- Y-linked and
- mitochondrial inheritance patterns
- autosomal dominant: manifested ikn the heterozygous state (at least one parent is usually affected) // affects both males and females
- autosomal recessive: both alleles at given locus are mutated // trait doesnt usually affect parents // 25% risk for each child
- X-linked: generally recessive in females - affects males at higher rate
- Y-linked - only affects males (father -> son)
- mitochondrial inheritance patterns: maternal inheritance (ova contain numberous mito. within abundant cytoplasm»_space; spermatozoa)
What is Cystic Fibrosis (CF)
- (?) disorder of (?)
- affects (?) in (?) glands and in the (?) lining of the (?), (?) and (?) tracts
- Abnormally (?) secretions
- Complications such as (?), (?) insufficiency, (?), (?), (?), (?), (?)
Autosomal recessive transmission
- inherited disorder of ion transport
- affects fluid secretion in exocrine glands and in the epithelial lining of the respiratory, gastrointestinal and reproductive tracts
- Abnormally viscous (thick) secretions - obstruct organ passages
- Complications such as chronic lung disease secondary to recurrent infections, pancreatic insufficiency, steatorrhea, malnutrition, hepatic cirrhosis, intestinal obstruction, male infertility
steatorrhea is an increase in fat excretion in the stools.
Describe how mutations in the CFTR gene manifests as Cystic Fibrosis
- 6 possible CFTR defects:
Autosomal Recessive pattern of inheritance
1. No funtional CFTR protein = nonsense; frameshift; canonical splice
2. CFTR trafficking defect: Missense; Amino acid deletion
3. Defective channel regulation: Missense; AA change
4. Decreased channel conductance: Missense; aa change
5. Reduced CFTR synthesis: splicing defect; missense
6. Decreased CFTR stability: Missense; aa change
Genetic and Environmental modifiers of CF?
- Polymorphisms in genes whose products modulate neutrophil funtion in response to bacterial infections
Modifier loci for severity of pulmonary disease in CF
eg Mannose binding lectin 2 (MBL2) // transforming growth factors B1 (TGF-B1) // interferon-related development of regulator 1 (IFRD1) - Bacteria (pseudomonas aeruginosa) can colonize the lower respiratory tract; concurrent viral infections predispose to such colonization
Define trinucleotide repeat disorder
Trinucleotide repeat disorders: consist of a group of human diseases, which are a result of an abnormal expansion of repetitive sequences and primarily affect the nervous system. These occur during various stages of human development