What are we made of?

Check yes or no

Do you have detached earlobes?

Can you roll your tongue?

Do you have dimples?

Are you right handed? Which one is my right hand ?

Do you have freckles?

Do you have naturally curly hair?

Do you have a cleft chin?

Do you have allergies?

Clasp your hands together. Is your left thumb over your right?

Can you see anything in this image? If you can not see the number 2 in this picture, you are color blind.

Is the hairline on your forehead straight?

Are you male or female?

Genetics Heredity: passing characteristics from parent to offspring Gene: segment of DNA or hereditary unit Genetics: branch of biology devoted to the study of heredity

Father of Genetics

What we know now loci

Mendel’s Theory of Heredity 1. For every trait, there are two copies of the gene (one from each parent)

Mendel’s Theory of Heredity 2.There are alternative versions of genes (alleles)

Mendel’s Theory of Heredity 3. When two different alleles are present, one is expressed (dominant)while the other is not visible (recessive).

Alleles can be Dominant or Recessive Dominant: always expresses itself ( capital letters are used to represent dominant alleles) Recessive: only expressed in absence of a dominant allele (lowercase letters are used to represent recessive alleles)

More terms If two alleles code for the same characteristic they are homozygous TT = homozygous dominant tt = homozygous recessive If the alleles are different they are heterozygous Tt = heterozygous Let’s practice

Dominant vs. Recessive Alleles in Creatures Triangle eyes are dominant Star eyes are recessive T Triangle eyes t Star eyes By looking at an individuals alleles, we can describe their Genotype: genetic makeup Phenotype: what they look like Genotype for star eyes tt Phenotype: star eyes Genotype for Triangle eyes TT Tt Phenotype: Triangle eyes

From the handout:

Activity Obtain 2 allele cards for each trait (no peeking) Write down your genotypes on the My Creature handout Write down your phenotypes on the My Creature handout Draw your creature

Evaluation Name three recessive traits in this alien. What are the two possible genotypes for this alien’s number of fingers? This alien’s genotype for number of legs is Ll. If it married another alien with genotype Ll, what is the probability that their baby would have five legs? Express as a fraction and percent.