A M E N D E L A P P R OAC H

GENETICS

GREGOR MENDEL

• The laws of inheritance were derived by Gregor Mendel, a nineteenth-century Austrian monk conducting hybridization experiments in garden peas• Between 1856 and 1863, he cultivated and tested

some 5,000 pea plant

• He only measured absolute characteristics, such as color, shape, and position of the offspring, rather than quantitative characteristics.

• Mendel picked common garden pea plants for the focus of his research because they can be grown easily in large numbers and their reproduction can be manipulated.

• Pea plants have both male and female reproductive organs. As a result, they can either self-pollinate themselves or cross-pollinate with another plant.

• In his experiments, Mendel was able to selectively cross-pollinate purebred plants with particular traits and observe the outcome over many generations. This was the basis for his conclusions about the nature of genetic inheritance.

• Phenotype: The expression of the genes in a living organism.

• Genotype: The gene composition of a living organism

TRAITS- WHAT ARE SEEN

• Dominant allele- the one allele that is expressed

• AA

• Recessive allele- the one allele that is not expressed but present.

• aa

Homozygous- when two identical alleles are present.

QQ

Heterozygous- when two diverse alleles are present. Qq or qQ

• “Law of Segregation”, states that every individual possesses a pair of alleles for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring.

• "Inheritance Law", states that separate genes for separate traits are passed independently of one another from parents to offspring.

LAW OF SEGREGATION

INHERITAGE LAW

MENDEL’SLAWS

31

PUNNETT SQUARE

9331

EXAMPLES

• Earwax• Brachydactyly (shortness of fingers and toes)• Eye Color• Hair Color

Recessive

Dominant Recessive/ Dominant

REVIEW

• Crashcourse• SAMPLES