THE SCIENCE OF HEREDITY

Genetics

Genetics Introduction 3 min.

Gregor Mendel

Was a priest in the 19th century. Mendel was the father of genetics.

◦ Genetics is the study of heredity.

Mendel used pea plants to cross pollinate. Bill Nye Discussing Mendel

Mendel’s WorkSome of Mendel’s questions were:

Why are some pea plants short while others are tall?

Why did some plants produce green seeds and other plants produced yellow seeds?

These characteristics that Mendel was describing are called traits.

Traits Traits - Characteristics that an organism can pass off to its offspring through its genes.

Examples of traits from pea plants:◦ seed color◦ height of plant◦ Smooth pod, pinched pod◦ pod color

What are some examples of traits from humans?

Genetic Traits in Humans

Genetic Traits Overview

Traits come from both parents We get ½ of our genes from one parent and the other ½ from the other parent.

Definitions Phenotype - An organism’s physical appearance or visible traits. What can be seen. (ex: freckles, curly hair)

Genotype - An organisms genetic makeup or allele combination. What can not be seen. (ex: AA, Aa, aa)

Allele – 2 forms of a gene, 1 from each parent and represented by lower case and capital letters. (ex: AA, Aa, aa) ◦ Think ALlele = ALphabet

Yeah, More Definitions Heterozygous - having two different alleles for a particular trait, one dominant and one recessive. (Aa)

Homozygous – having the same 2 alleles for a particular trait, both dominant or both recessive. (AA or aa)

Other Genetic Traits Tongue curling

LEFT HANDED OR RIGHT HANDED THUMB CROSSING

Other Genetic Traits

VULCAN FINGERS OR NOT HITCHHIKER THUMB

Other Genetic Traits

LONGER 2ND TOE BENT LITTLE FINGER

Other Genetic Traits

EYE COLOR FRECKLES

Other Genetic Traits

Earlobes

Hair on fingers?NO

YES

Widows peak

CURLY STRAIGHT

Curly hair

CLEFT SMOOTH

Chin

SMILE DIMPLES NO SMILE DIMPLES

Smile dimples

Please turn to page 116 in the green science book.