Unit 9- Genetics Part 2

Bellringer4/11/11

START A NEW BELLRINGER SHEET!

1. Create a Punnett Square that illustrates the cross between a Homozygous dominant female and a heterozygous male.

2. What are the phenotypic ratios?

Review of Terms

Homozygous: Two identical alleles

Heterozygous: two different alleles

Dominant: The trait will always be expressed if present, represented by a capital letter

Recessive: only expressed as a homozygous pair, represented by a lower case letter

Polygenic Inheritance

When multiple genes effect the same phenotypic character.

Example: Skin color in humansat least 3 genes control thevariation colors. The different combinations of these genes produces the variation.

Incomplete Dominance

A type of inheritance in which the phenotype of the Heterozygote (Aa) is an intermediate between the phenotypes of the two homozygotes (AA and aa)

Example: Straight hair is incompletely dominant over curly hair, the heterozygote intermediate is wavy hair.

CodominanceA type of inheritance in which both traits are

expressed in the heterozygote form.

Example: fur color in animals, petal colors in flowers.

Exit Slip 4/11/11

PUT ON BELLRINGER SHEET

1. What is the difference between incomplete dominance and codominance?

2. What is an example of polygenic inheritance?

3. A curly haired female crosses with a straight haired male and they have a wavy haired offspring. What type of inheritance is this?

Bellringer4/13/11

1. When two traits on separate alleles are both expressed, what type of inheritance is this?

2. What is an example of incomplete dominance?

Do Not touch the computers!

Sex-LinkedA gene that is located on either sex chromosome. If

the trait is located on the X chromosome it will only be passed to the offspring that receive that X chromosomes. If the trait is located on the Y chromosome it will only be passed to males.

These traits are crossed the same as Autosomal genes but are written alongside the X and Y chromosomes: XRXr XR Y (represents a gene located on the X chromosome)

Sex Linked

Multiple Alleles

More than two alleles exist for a particular gene. In humans, blood types are determine by the combination of 3 alleles, A, B, O. Each allele codes for a different carbohydrate in the blood.

Blood Types

Exit Slip4/13/11

1. What are the 3 alleles for human blood types?

2. What happens when 2 different blood types are mixed?

3. What is an example of a sex linked disorder?

4. What two sex chromosomes do males have?

Bellringer 4/19/11

1. What is a sex linked trait?

2. What are the two sex chromosomes?

3. What two chromosomes do males have?

4. Colorblindness is a recessive trait carried on the X chromosome. A female is a carrier for the disorder, she crosses with a male that does not have the disorder. What are their genotypes?

XCXc XCY

Pedigrees

A pedigree is a family history that shows how a trait is inherited over several generations.

Genetics

Exit Slip4/19/11

1.What gender is II-3?2.Does III-4 carry the

disorder?3.How many children

did II-1 and II-2 have?

4.Who is affected by the trait?

Bellringer 4/21/11

1. Is this trait dominant or recessive?

2. Autosomal or x-linked?

3. How many individuals of this family have the trait?

Genetic DisordersGenetic disorders are caused by inherited mutations

that disrupt the normal function of a gene. .

TechnologyCloning: the process of making an organisms or piece of

genetic material that is genetically identical to one that was preexisting. An egg cell donor provides a womb for the nucleus of a somatic cell to develop. The clone will be identical to the somatic cell donor, not the egg cell donor,

or the surrogate.

Stem Cells: a cell that can continuously divide and differentiate into various tissues. Embryonic stem cells can give rise to almost any type of cell or tissue type. Adult stem cells can be removed and used to grow more cells of only a few cell or tissue types.

Bellringer4/25/11

Turn in Pedigree Lab and Webquest

1. What does an egg cell donor provide for cloning?

2. When something is cloned, who will it be identical to?

3. Which of the disorders discussed is sex-linked?

4. If a female is a carrier of a sex linked disorder, what would be her genotype?

XHXh

Sickle Cell

Article ReviewAfter reading the article answer the following

questions:

1. What is the main idea of the article?

2. Explain what caused the blue color in the skin?

3. Is the gene recessive or dominant?

4. How was it possible for this disorder to continue to be inherited?

5. How has it started to “disappear?”

When you are finished, put your responses in the turn in tray!