Exploring Mendelian Genetics Through Family Trees: A Genetics Assignment

Historical timeline of genetics research

Your genetics assignment will provide you with an opportunity to explore Mendelian geneticsconcepts that you learned about in class. Students frequently report that they find thisassignment interesting. If you decide to involve family members or friends in your assignment,you will likely find it easy to generate interest in the topic.New advances in our understanding of genetics are being reported on a month to month basis.

Historical timeline of genetics research

1856 - Based on experiments with pea plants between 1856 and 1863, an Augustinian Monknamed Gregor Mendel led the way for the discovery of how “genes” as we know them now areresponsible for genetic traits (phenotypes) that we inherit and pass on from one generation tothe next in predictable ways.

1952 - A rare photograph of the DNA double helix was taken by Rosalind Franklin using X-Ray crystallography in 1952

1953 - James Watson and Francis Crick discovered the double helix structure of DNA. Theirdiscovery was partly made possible by the rare photograph of the DNA double helix taken byRosalind Franklin using X-Ray crystallography in 1952.

2003 - The Human Genome Project was completed ahead of schedule in 2003. This projectresulted in the successful mapping of the human DNA nucleotide sequence.

Today – you are researching and exploring the genetics of your familyFor a complete historical timeline of the major events in genetics research, see the NationalHuman Genome Research Institute web page for useful educational material on the humangenome. (National Human Genome Research Institute, 2014)Your assignment is largely based on the discoveries of Gregor Mendel. The family treeassignment follows Mendelian genetics principles. In order to be successful with thisassignment, you will need to be clear on how dominant and recessive phenotypes are inherited.

Choose assignment “A” or “B” or “C”

Individual instructors may have requirements that vary. Please consult your instructor beforeattempting the assignment.

Assignment A: Using your own family

Create a family tree (pedigree) that follows a single Mendelian trait (phenotype) through aminimum of three or four generations including a minimum of twelve individuals.

? Choose one phenotype, dominant or recessive, from those listed at the end of thishandout. Given the limited time available for this assignment, characteristics of appearanceare probably the best choice. If you choose to do a known inherited family condition such ashemophilia, hemochromatosis, or sickle cell anemia, you should consult your instructorfirst.Do not choose characteristics where there is no phenotypic or genotypic variation (i.e. allattached earlobes or all recessive). If you choose to do a phenotype that is not listed onthese pages, you must research it and get permission from your instructor.

? Your family tree must include a minimum of 3 (preferably 4) generations. If you wish tospeculate on potential phenotypes and genotypes of potential future children of you oranother family member, then include it in your family tree and note this in your legend. Besure that your legend clearly indicates the symbol that denotes any unborn, fictitiousindividuals.