Biolo1100 Chapter 10 Foundations of Genetics
  1. Gregor Mendel pioneered the study of inheritance   of observable traits, which we now understand is based on genes  .





     
  2. Mendelian inheritance exhibits predictable expression of dominant   and recessive   traits.





     
     
  3. A testcross   with a homozygous recessive   individual can be used to determine the genotype of a dominant   individual.

     
  4. Many traits exhibit non-Mendelian inheritance.
     
    • Incomplete   dominance results when alternative alleles are not fully dominant or fully recessive.

       
    • The human ABO blood group exhibits codominance  .


     
  5. Nondisjunction   may occur during meiosis, resulting in gametes with incorrect number of chromosomes, or aneuploidy  .

     
    • Survivable aneuploidies include trisomy 21, which causes Down   syndrome, and sex chromosome aneuploidies.




     
  6. Pedigrees   can be used to track the inheritance of genetic disorders, such as sickle-cell anemia   and Huntington's disease.