Chapter 20- Patterns of Inheritance Flashcards
Why the x allele is recessive?
- product will be synthesised even if you have one dominant allele
- need 2 recessive to prevent product being synthesised
One reason other than epistasis, why expected phenotypic ratio not obtained?
- autosomal linkage
- genes on same chromosome so inherited together
- if genes are close together there is less chance of crossing over
Using critical table. How can you say results are significant?
- difference is significant
- bc calculated value is greater than critical value of x
- this means 5% probability that results due to chance
- accept experimental. reject null
Genotype?
combination of alleles possessed by an organism
allele ?
version of a gene
Why a collection of small islands remote from mainland provides optiaml conditions for speciation?
- small gene pool
- all have diff environments so diff selection pressures
- geographically isolated
Why dwarfism can be described as a genetic condition?
- passed to offspring by parents
- caused by mutation/ allele
Why x can diffuse through cell membranes?
- small
- non polar
- so can pass directluy through phospholipid bilayer
Why one individual can only have 2 alleles for one gene?
- chromosomes are in pairs
- one allele on each chromosome of pair
How this allele could have become more common in population?
- natural selection
- provides selective advantage bc survival/ breeding
- allele passed on to next generation
- allele increases in frequency over generations
Using linkage, explain why these traits became more common.
-x gene and genes for these traits on same chromosome so inherited together
Using epistasis. Explain why these traits became more common.
Product of one gene affects expression of another via enzyme pathway
Using genetic drift. Explain why these traits became more common.
Random
Effect is stronger bc small breeding population
