Models of single-gene inheritance: Punnett squares
I can interpret and construct Punnet squares to show the inheritance of alleles of a single gene.
Models of single-gene inheritance: Punnett squares
I can interpret and construct Punnet squares to show the inheritance of alleles of a single gene.
Lesson details
Key learning points
- Most characteristics are influenced by multiple genes, but some are determined by just one.
- An individual will inherit two alleles for each gene, the alleles for a gene may be dominant or recessive.
- A Punnett square models inheritance of alleles showing possible genotypes of offspring as homozygous or heterozygous.
- Punnett squares are used to predict proportion of genotypes/phenotypes, or probability of occurrence in the offspring.
- Each instance of sexual reproduction is independent, so does not affect the probability for subsequent offspring.
Common misconception
A gamete has two alleles, Punnett square has too many alleles for gametes. Also that only four offspring are produced and therefore each will definitely have the genotype and phenotype shown.
Model the alleles within gametes so it is clear. Refer to half the gametes having each version, moving away from the idea of divisions of 4.
Keywords
Punnett square - A model used to show the inheritance of alleles from parents to offspring.
Gamete - A sex cell (i.e. sperm and egg) that carries half the genetic information required for an individual organism.
Genotype - The combination of alleles that an individual has for each gene.
Ratio - Shows hows how much of one value there is compared to another.
Probability - A measure of the chance or likelihood of an event occurring.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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Starter quiz
6 Questions
Exit quiz
6 Questions
has two different alleles for a gene
has two identical alleles for a gene
a measure of the chance of an event happening
shows how much of one value there is compared to another
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