Medical Genetics

Medical Genetics

Presentation lecture by:Dennis Anderson
Oklahoma City Community College
Human Anatomy and Physiology II
Mitosis

* Produces daughter cells with 46 chromosomes
* Used in growth and repair
* DNA is duplicated
* Doubled chromosomes form from duplicated DNA
* Each cms has 2 identical chromatids

Chromatid
Mitosis Metaphase
Chromosomes separate
Meiosis
Chromosomes line up in a double row.
Each each daughter cell gets doubled chromosomes
Double Filed Chromosomes
Gene
Allele
Dwarfism = D
Normal height = d
DD = Dwarfism
Dd = Dwarfism
dd = Normal height
Examples of Alleles
Dwarf Band

Dominant & Recessive Alleles
Homozygous
Heterozygous
Genotype
Phenotype
Codominant
Karyotype
Homologous Chromosomes
Mutation
Mutagen
Agent that causes mutations
Cigarette smoke
Pesticides
X-rays
Ulatraviolet light
Nuclear radiation
Homologous Pairs Separate
Fertilization
Nondisjunction
Trisomy
Sex Chromosomes
Autosomes
Chromosomes 1-22
X-Linked Traits
Normal Male
Normal Female
Trisomy 21
Down Syndrome
* Large tongue
* Flat face
* Slanted eyes
* Single crease across palm
* Mental retardation
o Some are not

Maternal Age & Down Syndrome
Trisomy 18
Edward Syndrome
* Heart defects
* Displaced liver
* Low-set ears
* Abnormal hands
* Severe retardation
* 98% abort
* Lifespan < 1 year
Trisomy 13
Patau Syndrome
* Cleft lip and palate
* Extra fingers & toes
o polydactylism
* Defects
o Heart
o Brain
o Kidneys
* Most abort
* Live span < 1 month

Klinefelter Syndrome
* Breast development
* Small testes
* Sterile
* Low intelligence
o Not retarded
Klinefelter Website
Turner Syndrome

* Short
* Not go through pruberty
* Produce little estrogen
* Sterile
* Extra skin on neck
Fetal Testing
Sickle Cell Anemia
* RBCs sickle shaped
* Anemia
* Pain
* Stroke
* Leg ulcers
* Jaundice
* Gall stones
* Spleen, kidneys & lungs
* Recessive allele, s codes for hemoglobin S
o Long rod-like molecules
o Stretches RBC into sickle shape
* Homozygous recessive, ss have sickle cell anemia
* Heterozygous, Ss are carriers

Hemophilia
Blood clotting impaired
Recessive allele, h carried on X cms
X-linked recessive trait
More common in males
Albinism
Amino Acids
Melanin Pigment
Enzyme
PKU Disease
Molly’s Story
Phenylalanine
Tyrosine
Enzyme

Medical Genetics.ppt