Mutation + Variation + Genome Organisation Flashcards
What are mutations?
The failure to replicate genetic information faithfully
Can affect whole chromosomes or single genes
Can be spontaneous or induced
Can be harmful, neutral or beneficial
Are the source of ALL genetic variation
Are necessary for natural selection and evolution
What is a mutagen?
Any agent that increases the mutation rate
What is a karyotype?
The whole set of a genome
What is polyploidy?
More than 2 sets of chromosomes
What is aneuploidy?
When one set of chromosomes is incomplete
Either missing a chromosome or an extra chromosome is present
What are the types of aneuploidy?
Nullisomy - both members of a pair are missing
Monosomy - one member of a pair is missing
Trisomy - one extra chromosome (usually lethal except on chromosome 21)
Do you need at least an X or Y chromosome?
X
Just a Y chromosome is always embryo lethal
What are translocations?
Exchange parts between NON-HOMOLOGOUS chromosomes
Happens most often on chromosomes where centromeres are towards the end of a chromosome - centromers get stuck together
When are inversion mutations less lethal?
When they dont involve the centromere
Pericentric - includes centromere
Paracentric - does not include centromere
What percentage of genes encode proteins?
1.5%
What base when changed will always change the amino acid?
2nd base
What amino acid causes albinism?
Tyrosinase
What amino acid change causes sickle cell anaemia?
Glutamic acid to valine
How much of the genome is non-coding?
95%
What are single nucleotide polymorphisms (SNPs) often used as?
Genetic markers for genetic studies
