Genetics

Life ScienceMr. P

Remember

• This can be one of the most difficult topics we cover because it is almost all new to you.

• You are meeting someone at an airport and you have never met them before. How would you describe yourself so that they know it is you?

• Think about it

• You are meeting someone at an airport and you have never met them before. How would you describe yourself so that they know it is you?

• Write down a few in the space in your notes…

• You are meeting someone at an airport and you have never met them before. How would you describe yourself so that they know it is you?

• Discuss it with your elbow partner

• You are meeting someone at an airport and you have never met them before. How would you describe yourself so that they know it is you?

• Share your responses

Traits

• Traits are the physical characteristics of an organism

What does that mean?

• A trait is different characteristics that a living thing has, such as hair color, eye color, and height.

Traits

• There are many traits, which are all unique to individuals, but come from your parents

Alleles

• The different forms of a trait are called Alleles.

• For example, hair color can be blond, brown, red, black.

Alleles

• The inheritance of a trait in humans is determined by one or more alleles.

Genes

• Alleles are based on your genes, which is what your DNA says you are going to look or, in some cases, be like.

Genes

• Every person has their own genes and they come from both of their parents.

Genes

• Identical twins have the same genes because they have the same DNA. This is why they look alike.

Genotype

• Genotype is an organisms genetic make-up

Phenotype

• Phenotype is the environments’ effect on the genetic make-up of an organism

Genotype vs. Phenotype

• You may have the genotype for blue eyes and brown eyes, but your phenotype would be brown eyes.

• This is because you have the alleles for both blue and brown eyes, but you only show brown eyes

Why?

• Brown eyes are dominant over blue eyes.

• Some alleles are dominant over others. If you have one allele for a dominant trait, that trait is shown.

What if there is no dominant trait?

• If there is no dominant trait, then you have the recessive trait.

• Both alleles (one from each parent) must be recessive in order for that trait to be expressed.

Example

• One parent has red hair. The other has brown hair. Brown hair is dominant over red hair. The child will most likely have what color hair?

Example

• Correct! Brown hair!

• However, this is not always the case, because the parent with brown hair can have the allele for both brown hair and red hair.

Confused??

• This can be really confusing which is why we are just learning the terms this week. We will start practicing how to do this next week.

Twin Studies

• Cloze reading-when I pause, you are going to say the next word. We will stop every now and then for you to read it to your self and to ask some questions.

• http://www.sciencenewsforkids.com/articles/20081210/Feature1.asp