Mr Dewhurst- patterns of inheritance Flashcards
what is interspecific variation
variation between different species
what is intraspecific variation
variation within species
how can the number if dopamine receptors influence obesity
people over eat to try and feel the pleasure of being full
what is continuous variation
controlled by both genes and environment
any feature that can me measured and put on distribution graph e.g., height, weight
what is discontinuous variation
qualitative- cannot be measured as is categories which are put into bar chart
controlled by small number of genes e.g., blood group, eye colour
allele
different versions of the same gene
genotype
alleles an organism has
phenotype
characteristics displaced by organism
what is the difference between dominant and recessive alleles
dominant- always expressed if present
recessive- only expressed if homozygous (same allele on each chromosome)
what is epistasis
more than one gene affecting characteristic
polygenic
multiple genes affect characteristic
monogenic
controlled by one gene
what is etiolation
plants don’t get enough light, grow long and spindly to find light
what is chlorosis
plant doesn’t produce enough chlorophyll as there is a lack f magnesium which is the prosthetic group if chlorophyll
what is meant by dihybrid
two characteristics controlled by different genes
what is codominance
both alleles are expressed and neither is recessive (both capital) - results in different function
what is meant by a gene being recessive
codes for a non functioning protein
What is meant by a recessive epistasis gene
There is a masked dominant allele, without that other genes don’t appear
E.g without the Y gene , no orange can be present even if orange is also dominant
What is meant by dominant epistasis gene
One dominant gene, copy of it masks expression of another gene
- e.g for colour white in squash plants only get other gene is homozygous recessive is present- then need dominant allele for either yellow or green
What is epistasis
One gene masking or suppressing expression of another
What is autosomal linkage
Some genes are inherited - on the same chromosome so not random/independent
What is an auto some
Chromosome that is not sex chromosome
how do you calculate chi-squared
add up all observed values, divide into genotypic ratio
this gets expected value
observed- expected value
square the value
divide by the expected value
add up sum of these value to give x2
how do you calculate degrees of freedom
n-1 (no.of categories- 1 )
