Honors Biology
Genetics Review Sheet
Mendelian genetics
1. Know and be able to explain Mendel’s Law of Segregation and Law of Independent Assortment.
Be able to relate both to meiosis.
2. Be able to recognize dominant and recessive alleles. Understand homozygous dominant,
heterozygous, and homozygous recessive genotypes, and the phenotypes they would produce.
3. Be able to perform a single gene cross.
4. Be able to perform a dihybrid (double factor or two-gene) cross, by being able to predict all the
possible genetic combinations that will occur, and the resulting probabilities of the offspring.
5. Be able to describe a test cross: how to do it, and what it is used for.
6. Be able to read a pedigree.
Non-Mendelian genetics
7. Sex-linked genes: describe why genes on the X chromosome are sex-linked genes. Be able to
perform a Punnet square for a sex-linked cross. Understand the concept of a carrier. (e.g.,
hemophilia, color blindness)
8. Incomplete dominance (e.g., flower color in Japanese five o’clocks)
9. Codominance (e.g., human blood type)
10. Multiple alleles (e.g., human blood type IA, IB, i)
11. Polygenic inheritance (e.g., human height, human skin tone)
12. Environmental impact on genes
13. Linked genes
Other
14. Be able to use the crossing-over frequency to estimate how close genes are on the same
chromosome.
15. Understand the molecular basis of recessive and dominant alleles—in other words, what makes
an allele a recessive allele?
16. Be able to explain why you only pass along new mutations that occur in your reproductive
system, and not other parts of your body.