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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?
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.
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