1. MENDELIAN GENETICS AND INHERITANCE
CHAPTER 14:
MENDELIAN GENETICS AND INHERITANCE

2. GREGOR MENDEL Born July 20, 1822 in Heinzendorf (Austria)
As a child, gardened and kept bees to entertain himself
Joined Abbey of St. Thomas (Brno) in 1843; occupied spare time with gardening

3. Mendel soon discovered that crossing different varieties of pea plants would produce characteristic traits of both varieties in the offspring. He dubbed these traits as “dominant” and “recessive” in correspondance to their appearance frequency.
The Gene Idea

4. THE BASIC IDEA
Mendel concluded from his studies that some traits have a disposition which favors them over other traits. These traits are Dominant. A dominant trait is marked by a capital letter.

5. RECESSIVE TRAITS
While the dominant traits (marked in grey on the previous slide) are more likely to be displayed than the recessives, if an organism carries 2 recessive alleles (gene types) then it cannot display the dominant (because it does not carry it). Therefore, an organism with this genotype (xx) would be considered homozygous recessive.

6. HETEROZYGOUS TRAITS and INCOMPLETE DOMINANCE
Organisms carrying a dominant and recessive allele (Xx) are considered heterozygous (one of each). An organism in this situation usually displays the dominant allele, except in cases of co- or incomplete dominance, in which an organism displays either both traits in competition or a compromise between the traits.

7. Applying Mendel’s Ideas
Mendelian genetics are the precursor to modern scientific projects such as Mapping the Human Genome and determining predisposition to disease via family history.

8. Mendel’s Studies, applied
Ever wondered if your going to develop a disease in your family’s history? Due to the research of Mendel, this takes a little simple studying (no expensive testing necessary, at least initially).
Ever wonder what color eyes your baby will have? Due to the work of Mendel, trait mapping is possible when a spouse’s traits are known.

9. Later life and decline
First publishing his works in a paper titled Experiments on Plant Hybridization, Mendel was ridiculed by the scientific community. When a reading at the Natural History Society of Brunn went awry, Mendel retired from the public eye, tending his garden in order to further his research on his own.

10. Death and Works
When Mendel died in Brno, Austria in 1884 of a Kidney Infection, the monastery burned all of his papers, and it was not until the 1900’s that the importance of his discoveries were realized, and he became a figure of the modern scientific circuit.

11. THE END