Gregor Mendel1822-1884

First person to trace the characteristics of successive generations of living things

He was an Augustinian monk who taught natural science and math to high school students.

The Monk Who Studied Pea Plants

Second child of Anton and Rosine Mendel

They were farmers in Brunn, Czechoslovakia

They couldn’t afford for him to attend college

Gregor Mendel then attended the Augustinian Monastery and became a monk

He was later sent to the University of Vienna to study.

Mendel was inspired to study variance in plants by his professors and colleagues

Gregor J. Mendel, O.S.A., experimental garden (35x7 meters) in the grounds of the Augustinian Monastery in Old Brno.Its appearance before 1922. Courtesy of Villanova University Archives.

The Monastery Garden with the greenhouse whichGregor J. Mendel, O.S.A., had built in 1870. Its appearance before 1902.Courtesy of Villanova University Archives.

Mendel studied the variances in traits displayed by pea plants

The traits observed included seed shape, seed color, flower color, and height.

He realized that the instructions for plant traits must be carried in an organism’s genetic material

Mendel’s Experiments

He took the male pollen from one plant and fertilized the female plant to cross traits (combine genetic material) .

After the seeds grew, he planted them to see what traits would appear in the next generation.

“F1 Generation”

“P Generation”

Mendel’s Results Y= Yellow allele

P Generation = Parents

F1 Generation=First Filial (means first son in Latin)

F2 Generation= Second Filial

Mendel realized that traits are inherited in numerical ratios!

He took a purebred green seeded plant and crossed with a purebred yellow seeded plant.

100% of the F1 always had yellow seeds!

F2 always had a 3:1 ratio!

Mendel’s Conclusions Y= Yellow allele

•He realized that each trait is controlled by two genes.

•He called this pair of genes that code for the same trait alleles.

•He realized that each plant inherits half of their genes from each parent.

•He called the trait that always showed up in the next generation the dominant trait (represented with a capital letter)

•He called the trait that seemed to hide in the next generation the recessive trait (represented with a lower case letter)

Mendel’s Findings Applied

YY yy

Yy YyYy Yy

YY yyYy Yy

F1 Generation

F2 Generation

Y= yellow allele (Dominant Trait)

y= green allele (Recessive Trait)

P Generation

YY= Yellow Purebreedyy= Green PurebreedYy= Yellow Hybird

From his studies, Mendel derived certain basic laws of heredity:

Hereditary factors do not combine, but are passed intact

Each member of the parental generation transmits only half of its hereditary factors to each offspring (with certain factors "dominant" over others)

Different offspring of the same parents receive different sets of hereditary factors.

Mendel’s works became the foundation of modern genetics

He later also crossed mice

His love of nature encouraged his interest in research

Also interested in meteorology and theories of evolution

It took seven years to prove laws of inheritance