Mutations as the raw material for evolution Flashcards
What is genotype?
The genetic makeup of an individual.
What is phenotype?
An observable, measurable characteristic of an organism.
What experiments did Mendel do?
He crossed peas producing coloured flowers and saw that the resulting flowers only had one colour, but when the second generation was produced there were some flowers with a different colour (white instead of purple).
What are alleles?
Variations of a particular segment of DNA.
What are homologous pairs?
The correspondence between the two sets of chromosomes - mum and dad.
Why don’t dark and pale moths end up creating grey offspring?
The trait for pale-dark colouration is controlled by a single locus.
Why is eye colour variable?
Controlled by loci and can therefore show intermediate states.
What is a dominant allele and what is a recessive allele?
Dominant - only one allele needs to be inherited to express the characteristic, recessive - two alleles need to be inherited to inherit the characteristic.
What are some genetic diseases caused by a single locus?
Cystic fibrosis and Huntingdon’s disease.
What is heterozygous advantage?
The idea that having one recessive allele rather than be homozygous for the dominant characteristic is more beneficial, such as in sickle cell anaemia - can provide immunity to malaria.
How do different forms of alleles develop in the first place?
Mutations when the genome is being replicated that will be passed onto daughter cells.
How can mutations be passed onto offspring?
They need to affect the germ line.
How can suboptimal alleles remain in a population?
Chance (especially in smaller populations), heterozygous advantage or it may only be deleterious after reproductive age.
What are the 4 types of mutation?
Point mutation, insertion, deletion and gene duplication.
Which type of mutation is most common?
Point mutation.
