 Pedigree Questions: 1. A circle represents a ________________ 2. A square represents a _____________ 3. A ___________ line connects a circle and square. 4. What are the roman numerals for? 5. Half shaded means an individual is a ___________ 6. Fully shaded means an individual is ____________

1. List all the Blood Phenotypes and their Blood Genotypes. 2. Cross Heterozygous A with Homozygous B 3. Cross O with Heterozygous B 4. Cross AB with Homozygous A !Determine G. Possibilities and G. Ratios! !Determine P. Possibilities and P. Ratios!

Mutations and Nondisjunction

Joke of the Day:

Mutations and Nondisjunction

" Mutation. It is the key to our evolution. It has enabled us to evolve from a single-celled organism into the dominant species on the planet."

The Human Genome: Facts Genome: Complete set of DNA/Genetic Material In every Cell: 46 Chromosomes or 23 Homologous pairs. Pairs #1-22: Autosomes - Pair #23: Sex Chromosomes – X and Y (Gender) Normal Male: 46XY Normal Female: 46XX 3.3 Billion Nucleotides 30,000 Genes (estimated)

Photograph of a full set of chromosomes in ordered pairs. (microscope)  Usually look at chromosomes in white blood cells  Identify chromosomal alterations that may result in a genetic disorder.

Normal Female Normal Male

 Mutation:  Changes in the DNA sequence that affect genetic code.  The ultimate source of genetic variability in a population.  Most Mutations are neutral

 If a mutation occurs during the formation of gametes, it may be passed to the offspring.  If a mutation occurs later in life inside a body cell, the mutation is not inherited.

 Gene Mutation : a change in a single gene  Mutation Example:  Point Mutation - One nucleotide (letter) in the DNA is changed.  Disorder Example:  Tay Sach’s Disease – Lipid accumulation in brain

 Chromosome Mutation: change in the whole chromosome.  Mutation Example:  Deletion, Duplication, Inversion, or Translocation  Disorder Example:  Fragile X – Severe learning disabilities

 During Meiosis, the homologous chromosomes fail to separate properly  Causes an abnormal number of chromosomes in the gametes and may lead to disorders.

Homologous chromosomes fail to separate Meiosis I: Nondisjunction Meiosis II

Trisomy 21: Down’s Syndrome  Occurs when there is an extra copy of chromosome 21. This causes problems with the way the body and brain develop.  Causes mild to severe mental retardation.  1 in 800 babies in the US is born with Down’s Syndrome.

 Turner’s Syndrome: A problem in females where she only inherits one X chromosome.. The woman is sterile.  Kleinfelter’s Syndrome: A problem in males where he inherits an extra X chromosome. The man is sterile. (47XXY Kleinfelter’s). (45XO Turner’s)

Kleinfelter’s SyndromeTurner’s Syndrome Turner’s Syndrome 45XO

 Jacob’s Syndrome: Genetic condition in which a human male has an extra male (Y) chromosome,. (47,XYY)  Occurs in 1 in 1,000 male births.  Increased average height  Delayed puberty  Learning difficulties  Speech problems