Step 3: Identify examples of dominant and recessive traits in humans and other living things

https://www.youtube.com/watch?v=TGLYcYCm2FM

The passing of traits from parents to child is the basis of heredity

What are examples of Traits?

Physical Traits: Characteristics of one's physical makeup likehair colour, eye colour, and height

Behavioral Traits: Characteristics of the way one acts

How do we get traits from our parents?

46 46

2323

46

Father Mother

spermegg

Zygote = New Individual

numbers in the circlesare the number of chromosomes

http://learn.genetics.utah.edu/content/inheritance/intro/ (3 clicks)

Why aren't biological siblings exactly the same?

Our 46 chromosomes are a random combination from our mother and father. Our brother's or sister's 46 chromosomes are a different random combination from our mother and father

(4 + clicks)

How can someone's environment affect their traits?

http://learn.genetics.utah.edu/content/inheritance/traits/

When traits are passed on to new individuals, what are the possibilities?

http://learn.genetics.utah.edu/content/inheritance/traits/

for each trait, there are 2 alleles (possibilities)

ex) hitchhiker's thumb and straight thumb. The alleles are represented by capital and lower case letters.

"h"

"H"

(Thumb trait)

Alleles will occur in pairs ex) HH, hh, Hh

Homozygous: having two of the same allele for one trait ex) HH or hh

Heterozygous: Having two different alleles for a trait ex) Hh

When the alleles of a trait are heterozygous, there will be a:

dominant allele (visible)

recessive allele (masked or hidden)

Law of Dominance: if a dominant allele is present, that trait will be shown

http://learn.genetics.utah.edu/content/inheritance/traits/ (trait inheritance)

How are traits determined?

The mother and father will each have 2 alleles for a trait represented as a:

Genotype: the alleles for a particular trait (letter combination ex) HH, Hh, hh)

because you only see one trait in a pair of alleles, this is called the phenotype

Problem: A father has brown eyes, a mother has brown eyes, and their new child has blue eyes?

Step 1: Create a key

trait eye colour : B = Brown (dominant) b = blue (recessive)

What are the allele pairs of each parent?

father: either BB or Bb

mother: either BB or Bb

explain?

step 2: create a Punnett Square

Punnett Square: a diagram used to predict the probability that an offspring will have a specific genotype

Possibility 1:

Father: BB

Mother: BB

results: 100% brown eyes 0% blue eyes

What are the possible genotypes and phenotypes?

possibility 2: Father: BB

Mother: Bb results: 100% brown eyes 0% blue eyes

What are the possible genotypes and phenotypes?

possibility 3: Father: Bb

Mother: Bb results: 75% brown eyes 25% blue eyes

What are the possible genotypes and phenotypes?

Where did this come from?

https://www.youtube.com/watch?v=Mehz7tCxjSE

Dragon Genetics Activity

- must choose a partner- partners must have 1 maledragon and 1 female dragon