Today's daily question was as follows:
If having a hitch-hiker's thumb is a recessive trait, and two parents with straight thumbs have a child with a hitch-hickers thumb, what does that mean about the genotypes of the parents and that of the offspring. (First determine the genotype of the child, then determine the genotype of the parents)
Alright - so - if it is a RECESSIVE trait, then we KNOW that the child MUST be homozygous recessive (hh) since he has a hitch-hickers thumb. Once we see that then we know that each parent had to have CARRIED the recessive allele. (It was not expressed though since each of them ALSO had to have the dominant allele in order to have a straight thumb) That means the parents were heterozygous for the trait (Hh)
We then started taking a look at our traits. Some of the traits we looked at were: Widows peak, tongue rolling, how we clasp our hands, dimple, freckles, etc....
What we SAW - the actual physical trait that we could see was our pheontoype. Based on those phenotypes we predicted what our genotypes were for each trait. If you showed the DOMINANT phenotype for a specific trait, there was TWO possible genotypes, either Homozygous Dominant (DD) OR Heterozygous (Dd). If, though, you showed the recessive trait, there was only ONE possible genotype, and that was homozygous recessive.
Good job today with all of this. Some classes then moved on to a concept map that looked at the relationship with the following terms: Heredity, alleles, genes, dominant, recessive, genotype, phenotype, Traits, parents, offspring.
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