The Central Dogma of Molecular Biology revolves around the expression of genes into a workable protein. This activity will allow you to show how the genes present in an individual’s genotype can affect the phenotype.
Genes are the units that determine inherited characteristics such as hair color and blood type. Genes are segments of DNA molecules that determine the structure of protein that our cells make. The sequence of nitrogen bases (“letters”) in the nucleotides determines the sequence of amino acids in proteins and thus the structure of proteins.
But how can the effects of a single gene be followed through several generations of a family? How can a person tell the difference between a dominant trait and a recessive trait? How does a gene differ from an allele?
By the end of this activity, the student should be able to demonstrate an understanding that (a) the genotype of an individual influences the phenotype (b) there are several possible combinations to genotypes – including homozygous dominant, heterozygous/carriers, and homozygous recessive, (c) in some cases the carrier’s phenotype is similar to that of the homozygous dominant, (d) differentiate between the expression of a dominant trait and a recessive one, and (e) use genetic diagrams to make predictions about possible inheritance of alleles.
In addition to the concepts described and followed in the activity, the students get to determine traits such as normal vs. anime hair in one pedigree challenge and hipster phenotypes vs. nerdy phenotypes in another.
TIME REQUIRED: 15 minutes to work through gene expression sequences and 15-20 minutes to answer follow-up questions.
ADDITIONAL SUPPLIES NEEDED: none