L3: Mitochondrial Disease and Chromosomal Abnormalities

inheritance:

diff b/t mitochondrial and nuclear DNA

M: inherited from mother

N: from all ancestors

summary:

mitochondrial DNA

-encodes genes for ATP production

-E metabolism

-higher mutation rate due to damage

summary:

nuclear DNA

-encodes most of the organism’s proteins → structural proteins, enzymes, regulatory factors

-cell processes

-lower mutation rate (repair mechanisms, etc)

recall: 

ataxia 

-neuro

-lack of mm control

term:

heteroplasmy

-more than one type of mitochondrial DNA (mtDNA) within the same cell or organism

-normal mtDNA

-mutant mtDNA

definition:

threshold effect - mitochondrial inheritance

-will only show clinical signs of a mitochondrial disease once the proportion of mutated mtDNA exceeds a certain critical level

-percentage is high enough to impair fx

chromosome numbers:

dog

-78

chromosome numbers:

cats

-38

chromosome numbers:

horses

-64

chromosome numbers:

bov

-60

A mutation changes a normal codon into a stop codon. What will be the consequences of this mutation?

-DNA and mRNA will be normal length

-the protein will be shorter in length

A mutation in the DNA of a coding gene that results in a change in the coded amino acid sequence is a:

-non-synonymous mutation

what are the general pedigree characteristics of an X-linked dominant mode of inheritance?

-A biased vertical pattern of transmission is observed → more females than males affected

-affected males pass trait to ALL their female offspring and NO male offspring

summary:

Robertsonian translocations

-chromosomal rearrangement where two acrocentric chromosomes fuse at their centromeres to form one large metacentric chromosome

-acrocentric chromosomes break near their centromeres and re-fuse

-reduction to 59 chromosomes

-common → reduced fertility

-can test for it