Predict offspring ratios based on a variety of inheritance
patterns (including dominance, co-dominance, incomplete
dominance, multiple alleles, and sex-linked traits).
patterns (including dominance, co-dominance, incomplete
dominance, multiple alleles, and sex-linked traits).
To the left is an example of a Punnett Square crossing a green pea plant with a yellow one. In this case, Yellow is the dominant trait and green is the recessive one. This means that for a pea plant to be green, it must be homozygous recessive. As can be seen, when the green plant is crossed with the yellow plant there is a 50% percent chance of having yellow pea plants and a 50% percent chance of the cross producing an offspring that is green.
Words to Know
- Dominant Trait: Always expresses itself when present.
- Recessive Trait: Only expresses itself when two of them are present.
- Homozygous: Both traits are the same, for example bb or BB.
- Heterozygous: Both traits are different, for example Bb or Aa.
- Phenotype: trait that is physically expressed.
- Genotype: Trait that is genetically present.
- Co-Dominance: When two alleles are present and are both expressed. If white is expressed in a rose, but red is too, you will get a pink rose.
- Incomplete Dominance: Results in spots. ex: Holstein Cattle.
- Multiple Alleles: Traits that are determined by more than one trait.
- Sex- linked traits: Traits that are passed down on the X chromosome of the twenty-third pairing, making it more likely for boys to be affected by the disorder.
- Autosomal Traits: Traits that both sexes are equally likely to inherit.