Post on 16-Dec-2015
transcript
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