Inherited change Flashcards
What is the genotype?
The genetic constitution of an organism. All the alleles an organism has.
What is the phenotype?
The observable or biochemical characteristics of an organism. It is a result of the interaction between genotype and the environment.
What is a gene?
A length of DNA that is a sequence of nucleotide bases, that code for a particular phenotype.
What is the locus?
The position of a gene on a particular DNA molecule.
What is codominance?
When two alleles both contribute to the phenotype.
What is monohybrid inheritance?
The inheritance of a single gene.
Why is it important to use large numbers of organisms in genetic crosses?
To obtain representative results.
What is dihybrid inheritance?
How two characteristics, determined by two different genes located on different chromosomes, are inherited.
How many parental genotypes are you given in a dihybrid cross for one parent?
4
What is the law of independent assortment?
Each member of a pair of alleles may combine randomly with either of another pair.
What is multiple alleles?
When there are more than two alleles, only two of which may be expressed at the loci of an individuals homologous chromosome.
How are the alleles represented in codominance?
As subscript next to the a letter that represent the gene.
What is a gene which is said to be sex-linked?
One which is carried on the X or Y chromosome.
Why are men more likely to inherit a recessive condition carried on the X allele?
Because they have the portion of chromosome that a dominant allele could be carried on, to nullify the effects of the recessive allele, missing on the Y chromosome.
Give an example of a sex-linked condition.
Haemophilia.
What is an autosome?
Any chromosome which isn’t a sex chromosome.
What is the name given for when 2 or more genes are carried on the same autosome?
Autosomal linkage.
What is epistasis?
When the allele of one gene affects of masks the expression of another in the phenotype.
What is the chi-squared test used to test?
The null hypothesis.
What are the 4 criteria for the chi-squared test?
- the sample size must be relatively large,
- the data must fall into discrete categories,
- only raw data counts and not percentages/rates etc,
- it is used to compare experimental results with theoretical ones.
How do you calculate chi-squared?
Sum of: (observed numbers - expected numbers) / expected numbers
