Alien GeneticsWhat are we made of?

Trait SurveyCheck 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?

It’s note taking time

GeneticsHeredity: 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 Heredity1. For every trait, there are two copies of the

gene (one from each parent)

Mendel’s Theory of Heredity2.There are alternative versions of genes (alleles)

Mendel’s Theory of Heredity3. 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 termsIf two alleles code for the same characteristic

they are homozygousTT = homozygous dominanttt = homozygous recessiveIf the alleles are different they are

heterozygousTt = heterozygous

Let’s practice

Dominant vs. Recessive Allelesin 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 makeupPhenotype: what they look like

Genotype for star eyes tt

Phenotype: star eyes

Genotype for Triangle eyes TT

Tt Phenotype: Triangle eyes

From the handout:Practice: For each genotype below, indicate whether it is heterozygous (He) or homozygous (Ho).

____RR

____Rr

____TT

____pp

____Hh

____BB

____Nn

____Ll

____ll

____ss

____Tt

____aa

Determine the phenotype for each genotype using the information provided

Round head is dominant over oval head

RR _____________________ Rr ______________________ rr ____________________

ActivityObtain 2 allele cards for each trait (no

peeking)Write down your genotypes on the My

Creature handoutWrite down your phenotypes on the My

Creature handoutDraw 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.