Genetics Notes Gregor Mendel 1 Mendel 1851 was

Genetics Notes

Gregor Mendel • 1. Mendel (1851) was a monk in central Europe • 2. One of his duties included caring for the monastery’s garden, which included pea plants.

3. Mendel decided to study pea plants, which was a very lucky choice. a. peas have many traits that exist in only 2 forms ( ex: tall and short) b. produce a large number of offspring c. produce perfect flowers so can produce purebred plants

4. Mendel’s first experiment: • Started with purebred plants • Pure tall plants and pure short plants • Crossed one of each • All of the offspring produced were TALL, there were no short plants and there were no “medium” plants • He wondered what happened to the “short” trait, if it disappeared or just got covered up by the tall trait

5. Mendel’s Second Experiment • Took individuals from 1 st experiment let them selfpollinate. • WOW!!!!!! ¾ of the offspring were tall and ¼ were short!!! • • The “short” trait did NOT disappear, it just got covered up by the tall trait • · Mendel called the one that got covered up “recessive” • The trait that masked the recessive trait he called “dominant”

6. Copy the chart from page 89 into notebook (without the pictures!) Pea traits Seed shape Seed color Seed coat color Pod shape Pod color Flower position Stem height Dominate Round Yellow Gray Smooth Green Side Tall Wrinkled Green White Pinched Yellow End Short allele Recessive allele

6. Mendel presented his results to a scientific society. No one thought his ideas were important and they refused to publish his work. His ideas were rediscovered in 1900 and many still hold true today. For this, he is called the “Father of Genetics”.

Vocabulary

Heredity The passing of traits from parent to offspring.

Purebred • An organism that always produces offspring with the same form of a trait as a parent.

Offspring the product of reproduction, a new organism produced by one or more parents.

Trait • a feature of an organism.

Genes A segment of DNA on a chromosome that codes for a specific trait.

Alleles The different forms of a gene

Recessive allele an allele that is masked when a dominant allele is present

Dominant allele an allele whose trait always shows up in the organism when the allele is present

Hybrid An organism that has 2 different alleles from a trait