Key Questions: How do mutations effect organisms?

DNA Mutation Cells use 4 base pairs of DNA to make about 20 amino acids These 20 amino acids combine to make up all the complex proteins in your body! A single mistake or mutation in one base pair can lead to the wrong amino acid- that leads to a mutated protein

Possible Causes of DNA Mutations Exposure to X-rays Exposure to UV light Exposure to certain chemical agents Exposure to radiation

Mutations Point Mutation: Base pair substitution- replace base pair with another Frameshift Mutation: Addition- add an extra base pair , change the reading frame Deletion- take out a base pair, change the reading frame ACG  ATG ACG  ACC / G ACG  AG_

A point mutation or a frameshift mutation? Which is worse? Which would have a greater affect on the eventual protein/trait? A point mutation or a frameshift mutation?

Mutations Point mutations and Frameshifts are mutations that change a portion of a DNA gene or RNA. An error during what process would cause a mutation in the DNA? An error during what process would cause a mutation in the RNA? Interphase- DNA replication Transcription or Translation

WHAT IF What if there is a mutation during MEIOSIS? Dun dun dun….

Chromosome Mutations Nondisjunction- separate unevenly in meiosis Translocations- part of chromosome moves to another chromosome Nondisjunction- separate unevenly in meiosis

Chromosome Mutations Deletion- part of chromosome deleted Inversion- segment of chromosome inserted backwards

Human Chromosomes Humans have 46 chromosomes normally. 22 autosomes (2 of each) and 2 sex chromosomes (girls X___, boys X__)

Human Chromosomes Humans have 46 chromosomes normally. 22 autosomes (2 of each) and 2 sex chromosomes (girls XX, boys XY)

Karyotype Karyotype- when scientists look at chromosomes and arrange them, and analyze them.

Karyotype Arranged by size Arranged by position of centromere First arrange normal chromosomes Try to arrange anything irregular

Staining chromosomes Stain Giemsa Staining stains the A and T rich portion of DNA dark. Banding patterns depend on genetic code Banding patterns unique to certain chromosomes

23 homologous pairs 46 chromosomes Normal Karyotype 23 homologous pairs 46 chromosomes

What are the sex chromosomes ?

X and Y

Chromosomal notation: 46,XY(normal boy) 46,XX(normal girl) 47,XX,+21 ABNORMAL EXTRA 21 what’s the disease?

Down Syndrome 3 chromosomes (21st pair)

When Meiosis Fails

produces 4 genetically different sex cells but same chromosome number Normal Meiosis: produces 4 genetically different sex cells but same chromosome number

An uneven splitting of the chromosomes during meiosis Nondisjunction An uneven splitting of the chromosomes during meiosis

Nondisjuction Animation

Do the research Describe the syndrome List cause List symptoms Get into groups of 2-3 and research the following topics (each group needs a comp) You will be assigned a syndrome Describe the syndrome List cause List symptoms Are their any treatments? Interesting facts

Pericentric inversion of chromosome 9 XYY Syndrome Klinefelter’s Syndrome Jacobsen Syndrome (Engnoth) Bloom Syndrome (Nall) Fanconi Anemia (NOT syndrome***) Philadelphia Chromosome (Bompard) Cri-du-chat syndrome (Kitzmiller) Down Syndrome (**) Turner Syndrome (Rinaudo) Wolf-Hirschhorn Syndrome

Pericentric inversion of chromosome 9 XYY Syndrome (Blye) Klinefelter’s Syndrome (Carlton) Jacobsen Syndrome Bloom Syndrome Fanconi Anemia (NOT syndrome***) (Phillips) Philadelphia Chromosome (Wolfe) Cri-du-chat syndrome Down Syndrome Turner Syndrome Wolf-Hirschhorn Syndrome

Down Syndrome Karyotype 3 chromosomes (21st pair)

Down Syndrome Traits mental retardation epicanthal folds over eyes flattened bridge of the nose

Nondisjunction in Sex Chromosomes

Turner Syndrome: Missing X

Turner Syndrome Symptoms short stature sterile webbed neck skeletal disorders

XYY Syndrome 5-10 born each day in USA Falsely called “superman” or “criminal” syndrome. 5-10 born each day in USA

XYY Symptoms taller more hairy heavy facial features delays in learning & language violent tendencies ????

Klinefelter Syndrome: XXY

Klinefelter Symptoms underdeveloped male traits mammary development learning disabilities language delays infertility