In order to use a test-cross to determine the genotype of an individual expressing the dominant phenotype one must assume that the animal inherited at least one dominant gene from either of their parents.
To determine the genotype of an agouti cat one would assume that the cat has at least one dominant A gene.
Population geneticists prefer to work with codominant genes because they want to experiment with these types of genes in order to better understand them.
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| The possible genotypes that could result from a cross between a tortoiseshell and black cat that are both homozygous BB. |
The cats resulting from the cross displayed in the table above would all be homozygous BB and have black fur.
A striped coat, as opposed to a solid coat, would have a positive effect on the fitness of a wild cat because the stripes would better blend in with the diverse environment that the cat is in, making it less noticeable to predators.
If you mated two white cats, you could not be confident of always obtaining white progeny because the cats may not both be pure white. They could also be albino or spotted.
Allele frequency is determined by the parents' alleles. A dominant allele is not always the most frequent allele at a locus due depending on the presence of hidden recessive alleles carried by the parents.
Manx cats have no tail and relatively long rear legs. Because of this, the genotype of a Manx cat is tt. I do not expect the frequency of Manx cats to increase over time because both of their genes are recessive which, when mixed with other species, will be masked by the dominant genes.
Did Mendel Fudge His Data?
The chance of agreement between the observed and expected frequencies of smooth and wrinkled seems too close.
I conclude on the basis of this one set of results that Mendel did, in fact fudge his data a bit because the results appear to close to his prediction than would happen in real life.
Blood Types
Blood type O is not possible in this situation because the child would have to receive either type A or B from his mother and type B or O from his father.
If a mother is type O+ and the father is A- the offspring's blood type would be either A or O, depending on if the father is homozygous or heterozygous.
If the mother of a child is blood type O+ and the child is A-, the father would be blood type A or AB.
The father could have blood type A or B.
A father would have to not be blood type O or A in order for his son to be blood type B+ if the mother is A.
No, due to their blood types it is very unlikely that they all have the same biological father.
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I agree with you in the Mendel's and Fisher's experiment!!!!
ReplyDeleteElvira, say more... what did you agree about.
ReplyDeleteSam, nice organization. This set up make it easier to read your responses.