Genetics

Gregor Mendel

• Genetics- The study of biological inheritance• Gregor Mendel= Austrian monk in the 1800s

that laid the groundwork of genetics.– He used pea plants to look for specific inherited

traits (shape, color, height, etc.)

http://www.thechartrands.com/uploaded_images/P3170047-779418.JPG

http://farm1.static.flickr.com/70/223024576_6ded872ae0.jpg

http://jugalbandi.info/wp-content/uploads/2007/07/img_7660-1.jpg

– He controlled mating and fertilization

• Mating of 2 organisms = cross

Mendel controlled thefertilization of his pea plantsby removing the male parts,or stamens.

He then fertilized the femalepart, or pistil, with pollen froma different pea plant.

– He came up with 3 conclusions:• 1) Traits are inherited as specific units.• 2) Organisms inherit two copies of each gene, one

from each parent.• 3) The two copies separate during gamete

formation.

*2+3 = law of segregation

Using Genes to Trace Inheritance• gene- piece of DNA with specific instructions• locus- location of gene• allele- any forms of the same gene at the

same locus

http://mygenetic.files.wordpress.com/2009/04/allele.jpg

* Each parent donates one allele for every gene.

• genotype = the makeup of a specific set of genes.

• phenotype = the physical appearance of a trait.

Recessive expressed only when 2 copies are present!

• Dominant alleles are represented by uppercase letters; recessive alleles by lowercase letters.

Order of dominance: brown > green > blue

???