genetics part ii. nature vs. nurture what you are born with (your genes) only determines part of how...

Genetics Part II

Nature vs. Nurture• What you are born with (your genes) only determines

part of how you will develop (nurture)• Gene Expression: Genes need to be “turned on” or

activated to create specific proteins. Genes are influenced by other genes and they are influenced by the environment

• Genetic Predisposition: May have the genetics for a trait, however, the gene/genes may never be activated. “At-Risk” … you may or may not even have the genes.

• You control part of your nurture HOWEVER some is out of your control (examples of nurture that is out of your control: Air quality, your mother’s diet while she was pregnant)

Vincent

• Genetically predisposed (99% probabilty) for heart failure

• Yet never has heart troubles• Assumes the identity of Jerome Morrow

Jerome

• Genetically “superior” – however still fails

In-Vitro Fertilization• Egg and sperm fertilized outside the human

body

Patterns of inheritance• Autosomal Dominant• Autosomal Recessive• Co-dominance / Incomplete Dominance• Multiple Alleles• X-linked• Non-Disjunctive disorders• Polygenetic traits

Polygenic traits• All the traits Mendel studied were

MONOgenetic (caused by a single gene)• Most traits are caused by multiple genes (POLY

= “MANY”) • Examples: Human height, intelligence

Sex-Linked Traits

• Gene located on the X Chromosome

- Color blindness- Hemophilia

You a man. Y. Yes that is correct!

Non-disjunction• Result of when during Meiosis (the formation

of gametes) chromosome pairs do not separate correctly – Thus Mendel’s law of segregation is broken

• Results in individuals with too many or too few chromosomes

• Examples: Downs Syndrome (Trisomy 21) and Turners Syndrome

Down Syndrome

Amniocentesis

• Using a needle amniotic fluid is removed from the women and tested• Much different from an ultrasound

or sonogram that only uses sound waves to create a picture of the baby

What is a Pedigree?

• A pedigree is a chart of the genetic history of family over several generations. A “family tree”

• Scientists or a genetic counselor would find out about your family history and make this chart to analyze.

Constructing a Pedigree

• Male

• Female

Connecting Pedigree Symbols

• Married Couple

• Siblings

Examples of connected symbols:

Example

• What does a pedigree chart look like?

Genetic DisordersAutosomal Recessive Disorders• Cystic Fibrosis• Sickle Cell Anemia• Tay-Sachs• PKU (Phenylketonuria)

Autosomal Dominant Disorders• Huntington’s• Marfan Syndrome

Simple Human Traits

Monogenetic with only two alleles: Dominate and Recessive

(Most human traits DO NOT fall into this category)

Cheek Dimples• Indentations along

side of mouth

• Dominant

Cleft Chin

• Indentation in chin

• Dominant

Earlobes• Can be free or attached

• Free are dominant, attached recessive

Face Freckles

Dominant

Hitchhiker’s Thumb• Ability to bend

thumb backwards at a 45-degree angle

• Recessive

Widow’s Peak• V-shaped point in

hairline

• Dominant

Morton’s Toe• Second toe longer

than first toe

• Recessive

Tongue Rolling

Dominant