Case 10: The truth about cats and dogs. BBS1001 2023/2024
6 oktober 2023
Keywords:
- Genetic changes
- Somatic and germ cell mutations
- DNA sequences
- Common ancestor
- Genome
- Phylogenetic tree
Problem statement:
Mutations and genetic evolutions
Brainstorming:
Types of mutations:
- Point mutation (located on DNA sequence)
o Deletion
o Substitution (sense and missense)
o Insertion
- Chromosomal mutation
o Inversion
o Translocation
o Aneuploidy, polyploidy
- Genome mutation
- Frameshift
Effect of mutations phenotype and genotype
Phylogenetic tree Parsimony method, UPGMA method
Learning goals:
1. Different types of mutations.
o DNA
o Chromosomal mutation
o Examples
2. What is a phylogenetic tree.
o What is it?
o How does it work?
o Two methods UPGMA and parsimony.
o Make phylogenetic tree from case.
3. Effects of mutations
o Missense mutation
o Neutral mutation
o Non-sense mutation
o Reverse mutation
o Suppressor mutation
, Case 10: The truth about cats and dogs.
1. Different types of mutations.
DNA mutation
Deletion
Deletions are mutations in which a section of DNA is lost or deleted.
Example:
- Cri du chat syndrome, deletion of certain genes on chromosome
5. (intellectual disability, high-pitched cry)
- Di George’s syndrome, deletion of certain genes on chromosome 22. (heart defects
and learning difficulties)
Substitution
A substitution is a mutation that exchanges one base for another.
Three types:
- Silent substitution but no change in amino acid.
- Missense substitution, amino acid changes.
- Nonsense substitution, amino acid change to a stop codon.
Which cause the protein to be non-functional.
Example:
- Sickle cell anemia, caused by a substitution in the beta-hemoglobin gene, which alter
a single amino acid in the protein. (shortage of red blood cells)
Insertion
Insertions are mutations in which extra base pairs are inserted into a new
place in the DNA.
Example:
- Fragile X syndrome, change in the Fragile X Messenger Ribonucleoprotein 1 (FMR1)
gene. (intellectual disability)
Frameshift
Since protein-coding DNA is divided into codons three bases long,
insertions and deletions can alter a gene so that its message is no longer
correctly parsed.
Example:
- Tay Sachs disease, mutation in the enzyme hexosaminidase A. (development slows
and muscles begin to weaken)
Chromosomal mutation
Inversion
During inversion, a portion of the chromosome is reversed and gets inserted
back into the chromosome.
Two types:
- Pericentric the inversion encompasses the centromere.
- Paracentric it only involves the short or long arm of the
chromosome (not the centromere)
6 oktober 2023
Keywords:
- Genetic changes
- Somatic and germ cell mutations
- DNA sequences
- Common ancestor
- Genome
- Phylogenetic tree
Problem statement:
Mutations and genetic evolutions
Brainstorming:
Types of mutations:
- Point mutation (located on DNA sequence)
o Deletion
o Substitution (sense and missense)
o Insertion
- Chromosomal mutation
o Inversion
o Translocation
o Aneuploidy, polyploidy
- Genome mutation
- Frameshift
Effect of mutations phenotype and genotype
Phylogenetic tree Parsimony method, UPGMA method
Learning goals:
1. Different types of mutations.
o DNA
o Chromosomal mutation
o Examples
2. What is a phylogenetic tree.
o What is it?
o How does it work?
o Two methods UPGMA and parsimony.
o Make phylogenetic tree from case.
3. Effects of mutations
o Missense mutation
o Neutral mutation
o Non-sense mutation
o Reverse mutation
o Suppressor mutation
, Case 10: The truth about cats and dogs.
1. Different types of mutations.
DNA mutation
Deletion
Deletions are mutations in which a section of DNA is lost or deleted.
Example:
- Cri du chat syndrome, deletion of certain genes on chromosome
5. (intellectual disability, high-pitched cry)
- Di George’s syndrome, deletion of certain genes on chromosome 22. (heart defects
and learning difficulties)
Substitution
A substitution is a mutation that exchanges one base for another.
Three types:
- Silent substitution but no change in amino acid.
- Missense substitution, amino acid changes.
- Nonsense substitution, amino acid change to a stop codon.
Which cause the protein to be non-functional.
Example:
- Sickle cell anemia, caused by a substitution in the beta-hemoglobin gene, which alter
a single amino acid in the protein. (shortage of red blood cells)
Insertion
Insertions are mutations in which extra base pairs are inserted into a new
place in the DNA.
Example:
- Fragile X syndrome, change in the Fragile X Messenger Ribonucleoprotein 1 (FMR1)
gene. (intellectual disability)
Frameshift
Since protein-coding DNA is divided into codons three bases long,
insertions and deletions can alter a gene so that its message is no longer
correctly parsed.
Example:
- Tay Sachs disease, mutation in the enzyme hexosaminidase A. (development slows
and muscles begin to weaken)
Chromosomal mutation
Inversion
During inversion, a portion of the chromosome is reversed and gets inserted
back into the chromosome.
Two types:
- Pericentric the inversion encompasses the centromere.
- Paracentric it only involves the short or long arm of the
chromosome (not the centromere)
