Monogenic inheritance Flashcards
1
Q
How are the inheritence of genes from one generation to the next shown?
A
- genetic cross
- most commonly the inheritence of a single gene is shown
- this is known as mongenic inheritence
2
Q
What are the steps in performing a genetic cross? (enbsure that your diagram explkains fully what is happening to the genes of an organsim during fertilisation)
A
- state the phenotype of both parents
- state thge genotype of both parents
- assign a letter code to present the gene being stuidied
- capital letter used to represent dominant etc.
- e.g. B brown fur (dominant), b white fur (recessive)
- state the gametes of each parent
- circle the letter
- use a Punnett Square to show the results of the random fusion of gametes during fertilisation
- state th e propotion of each genotype produced among the offspring
- percentage or ratio
- state the corresponding phenotype for each of the possible genotypes
- must be clear that you know which phenotype results from each genotype
3
Q
What is the name given to the offspring of a hetrozygous genetic cross?
A
the F2 generation
4
Q
When does codominance occur?
A
- when two different alleles occur for a gene
- both of which are equally dominant
5
Q
What is the result of codominance?
A
- both alleles of the gene are expressed in the phenotype of the organism is present
6
Q
What letters are used to show codominance?
A
- upper and lower case letters are not used
- this would imply one allele in dominant and the other is recessive
- instead, a letter is chosen to present the gene
- the different alles are the represented using a second letter which is shown as a superscript
7
Q
How is blood group determined ? How is this different?
A
- blood group is determined by a gene with multiple alleles
- some genes have more than two versions
- as an organism only carries two versions of the gene
- only two alleles can be present
