Warm-Up / EOC Prep 1. External sources, such as radiation or chemicals, can cause mutations in genes or entire chromosomes. For a mutation to pass on to offspring, it must occur in a a. sex cell b. muscle cell c. bone cell d. brain cell 2. In snapdragons, the combined expression of both alleles for flower color produces a new phenotype that is pink. This illustrates incomplete dominance. The Punnett square above shows that both the white and red snapdragons are homozygous. Which of the following would be the correct product from a cross between two heterozygous pink snapdragons? a. 2 red, 2 white b. 2 red, 1 pink, 1 white c. 1 red, 2 pink, 1 white d. 1 red, 1 pink, 2 white

Agenda Warm-up Notes Genetic Disease Project Clean-up Cool-down

What is this called? What is it used for? What can you tell me about the person?

Genetic Diseases

DNA is the genetic material that passes from generation to generation. DNA is organized into chromosomes Humans have two copies of 23 different chromosomes. That makes 46 chromosomes total. Genes are segments of DNA that code for a specific protein or trait.

Inheritance Mendalian Inheritance – AA Homozygous dominant – Aa Heterozygous dominant, carrier – aa Homozygous recessive CoDominance, Incomplete Dominance – Intermediate trait is expressed Sex-linked Inheritance – Gene is only on X chromosome, males are affected more than females because they only have on X chromosome

Nondisjunction – Chromosomes get stuck together. One sex cell ends up with more chromosomes, others end up with less.

Mutations You can think of DNA as one long sequence of letters. DNA polymerase is an enzyme that acts as a “spell-checker” “Misspelling” of base pairs during DNA replication result in mutations if they are not caught by DNA polymerase

Types of Mutations Point mutation: Just one base is changed for another base. This is just a single change in amino acid. Insertion: a new base pair is added into the sequence of DNA. This can result in a phase- shift, or all amino acids after that point are different Deletion: a base pair is taken away or deleted from the sequence. This can result in many changes in amino acids.

When chromosomes don’t separate during meiosis (super bad) Nondisjunction

A technique used to determine the genetic traits of a baby before it is born by taking a picture of the chromosomes AMNIOCENTESIS

A picture of the chromosomes is called a Karyotype. What can you tell from the karyotype below? Normal female (note the XX chromosomes)

What can you tell from the karyotype below? Normal male (note the X and Y chromosomes)

Klinefelter Syndrome Chromosomes: 47, XXY Have male genitalia and internal ducts, but underdeveloped testes Do not produce sperm Slight enlargement of the breasts Risk: 1 out of every 500 male births

Turner Syndrome Chromosomes: 45, X Has female external genitalia Underdeveloped ovaries Short (under 5 feet) Webbed Neck Broad, Shield-like chest Risk: 1 out of every 3000 female births

Down Syndrome A result of nondisjunction Chromosomes: AKA trisomy 21 (47, 21+); 3 copies of the 21 st chromosome Short Small round heads Protruding, furrowed tongues which cause mouth to remain partially open Retarded (IQ below 70) Shortened life expectancy (<50) Prone to respiratory disease and heart malformations Have 15x higher chance of getting leukemia Risk: Chance of having a baby with Down syndrome goes up as the mother gets older

REVIEW A chart that shows how traits are passed within a family is called…

pedigree

In a pedigree, squares = _____ and circles = ______

Males and females

Name two sex-linked traits

Hemophilia and colorblindness

A picture of your chromosomes is called a…

karyotype

If a female has one normal x, and one recessive x for colorblindness, will she be colorblind?

No, she is a carrier

Genetic Disease Project Instructions / Rubric- on the back of your notes. Worth 1 Test Grade! DUE Tuesday, November 1st, 2011

Cool-Down 1- If you saw a baby with a webbed neck, what genetic disorder do they most likely have? 2- A karotype has 2 X and 1 Y chromosome. What genetic disorder? 3- Which disorder results from nondisjunction of chromosome 21?

Warm-up Name the correct mode of inheritance… 1- A combination of the dominant and recessive creates a new phenotype. 2- Neither allele is dominant, but both are expressed at the same time. 3- The trait is found on either the X or Y chromosome.