two types of mutations gene mutation: single gene defective insertion substitution deletion...
TRANSCRIPT
Two Types of Mutations Gene mutation: single gene defective
Insertion Substitution Deletion
Chromosomal mutation: missing or extra chromosome Monosomy Trisomy Deletion
Either can involve autosomes (chromosomes 1-22) or sex chromosomes
Autosomal Disorders
Disorders involving the 22 pairs of chromosomes that are NOT sex chromosomes (X,Y).
Can result from Gene mutation: defective gene
on autosome Chromosomal mutation: loss
or gain of autosome
Aa
Aa Aa
aaAaAA
Autosomal DisordersGene Mutations
1- Cystic Fibrosis Recessive disorder Mutated gene on
chromosome 17. Characterized by excessive,
THICK secretion of the mucus in the body.
Autosomal DisordersGene Mutations
2- Huntington Disease Dominant disorder Mutated gene on
chromosome 4 is responsible.
Causes degeneration of neurons producing dementia, and random jerking movements.
Autosomal DisordersGene Mutations
3- Phenylketonuria (PKU) Recessive disorder Mutated gene on chromosome
12 is responsible4- Sickle-Cell Anemia 1 of 12 U.S. African Americans Recessive disorder Mutated gene on chromosome
11
Autosomal DisordersGene Mutations
5- Tay-sachs Disease Recessive disorder European Jewish ancestry. Mutated gene on
chromosome 15 Tay-sachs—One Wrong Letter
Autosomal DisordersChromosomal Mutations
Down Syndrome 1 in 1,000 live births. Extra Chromosome 21 Risk increases with
mom’s age Pregnancies of women
over age 35 accounts for20% of Down syndrome
births
Sex-Linked Disorders Involve the sex chromosomes Recessive gene on the X chromosome is more
likely to be expressed in males ***Y chromosome has no 2nd allele that might
counteract the gene on the X chromosome!
Sex-Linked DisordersGene Mutations
1- Color Blindness X-linked recessive disorder Gene mutation on X
chromosome 1 of 10 males
2- Hemophilia X-linked recessive disorder Gene mutation on X
chromosome. 1 of 5,000 males Interfere with normal blood
clotting
Sex-Linked DisordersChromosomal Mutations
1- Klinefelter Syndrome (XXY) 1 of 1,000 males. Extra X chromosome
Sex-linked DisordersChromosomal Mutations
2- Turner’s Syndrome (XO) 1 of 10,000 females One of X chromosomes is either
missing or inactive Have immature female appearance
and lack internal reproductive organs.
GENETIC DISORDERS
Autosomal DisordersChromosomes 1-22
Sex-Linked DisordersSex Chromosomes X and Y
Gene Mutations1 gene mutated
on chromosomes 1-22
ChromosomalMutations
Extra or missing chromosome 1-22
Gene Mutations1 gene mutated
on X chromosome
ChromosomalMutations
Extra or missing Sex chromosome
EXAMPLES?
How Do We Know About All of Our Genes?
Human Genome Project Began in 1990
Goals: Determine complete sequence of the
3 billion DNA bases in human DNA Identify all human genes for further
biological study
The Unknown
Gene number, exact locations and functions
Gene regulation DNA sequence organization Chromosomal structure and
organization
Ethical, Legal and Social Issues
Fears Genetic information used to harm or
discriminate Deny access to health insurance Deny employment Deny education Deny loans?
DNA Databases