What is your strategy for breeding disease resistant tigers?
– I tried to match tigers who have two alleles for resistance. Since two non resistant alleles and tigers who have one of each alleles it won’t be resistant, I tried not to match tigers having (DD) or (Dd).
How can you produce disease resistant offspring if you start with two parents who are not resistant?
– If you choose two tigers who are both heterozygous parents there is a chance that they can produce disease resistant offspring. For example, there is a one in four chance of the offspring having the disease resistant. In fact, two parents who are not resistant can have (dd), (Dd), (Dd) and (DD) offspring. To produce disease resistant offspring there is 25 percent.
Which allele is dominant and which is recessive?
– A dominant allele always shows even if the individual only has one copy of the allele. For example, the allele for not resistant is dominant.
– A recessive allele only shows if the individual has two copies of the recessive allele. For example, the allele for resistance is recessive. So, if the tiger carries two alleles for resistance (dd) the tiger will only be resistant.
How do parents who have a phenotype which is not resistant produce offspring who have a phenotype that is resistant?
– The physical appearance of a trait is called a phenotype. The phenotype is determined by the genotype or set of genes inherited for that trait.
– The relationship between phenotype and allele depends on the presence of dominant or recessive traits. For example, since having an allele which is not resistance is dominant and having an allele which is resistance is recessive there three possible genotypes. The possible genotypes are (dd), (Dd) and (DD). There are 25 percent (1/4) to produce offspring who have phenotype that is resistant. Not only that, the phenotypes will be not resistant or resistant allele.
What is a punnet square and how do you make use of it to predict outcomes of a mating?
– A punnet square is a type of grid used to show the possible outcomes of offspring from their parents.
– To use the punnet square we should know the genes involved with the trait, the genotypes of the parents and whether certain alleles are dominant or recessive. If we mate two heterozygous parents for one trait is only controlled by one gene, we will have a punnet square with four blocks. Than we can predict the outcomes of the offsprings.