Exploring

Dominant and

Recessive Traits

Where do traits come from?

Your parents pass them down through genetic traits.

You receive half of your genes from each parent

Each person has about 70,000 pairs of genes.

Genes can be dominant or recessive

Dominant Traits vs.

Recessive Traits

Dominant trait-Strongest trait

Dominant trait-Masks or covers up the weaker trait

Common Misconception

Recessive Traits are not rare traits.

Dominant or recessive traits may be more common in a

population.

Example: Blonde hair is very common in parts of

Scandinavia.

Example: The trait of having six fingers on one hand is a

dominant trait!

DNA fun facts

How long does it take one of your cells to completely copy its DNA?

8 hours

In the human DNA code is made up of base pairs: A-T and G-C on each side of the DNA strand. How many base pairs are in a DNA strand?

3 billion

If you were to recite the order of the ATCGs in your DNA starting tomorrow morning, at a rate of 100 nitrogen bases per minute, how long would it take you to recite one entire DNA strand if you didn’t stop to eat, drink, sleep or go to the bathroom, etc?

57 years

DNA fun facts

Autosomal cells have how many chromosomes?

46

Sperm and egg have how many chromosomes?

23

If you were to stretch out the DNA from your 46 chromosomes in just one cell and lay it end to end, how long would it be?

Over 2 yards

If the total DNA in one person were laid out in a straight line, how long would it be?

30 times the distance to the sun

DNA fun facts

How many cell nuclei could you fit across the period on

your paper?

1000

How many threads of DNA could you fit across the same

period?

1 million

If you wanted to store all the information from a strand

of DNA on a computer, how much storage space would it

take up?

3 GB

DNA fun facts

How genetically similar are you to any other

random human on the planet? (percentage wise)

99.9%

How much genetic material do we as humans share

with the bacteria e. coli? (percentage wise)

7%

How much genetic material do we as humans share

with earthworms? (percentage wise)

21%

DNA fun facts

How much genetic material do we as humans share with the a zebra

fish? (percentage wise)

85%

How much genetic material do we as humans share with a mouse?

(percentage wise)

90%

How much genetic material do we as humans share with a chimpanzee?

(percentage wise)

98%

What percent of our DNA codes for proteins?

2%

The dominant trait is always the better trait to have.

False

Help!

An alien from outer space teleports into the class. Upon

seeing the class,

the alien concludes that all humans look alike. It is your

job as a class to assist the alien in differentiating

humans from each other.

Form a list with the people around you.

On a sheet of paperYes Class Frequency No Class Frequency

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

Earlobe

Darwin’s Ear Points

Dimples

Tongue Rolling

Left handed

Freckles

Widows Peak

Curly Hair

Longer 2nd toe

Hair Color

Eyes

Thumb

Butt Chin/Cleft Chin

Skin Pigment

Vision

Tongue to Nose

Mid-digit hair

Dominant Recessive

Index finger longer than ring finger

Bent little finger

Hand Clasping

Vulcanism

Questions to think about

Which traits are most common in your class? Least common?

Create a bar graph of the classroom responses.

What evidence (data) suggests that humans are similar?

Different?