Human HeredityHuman HeredityHuman HeredityHuman Heredity

The Human GenomeThe Human Genome

Chromosomes• Humans have 46 individual or 23

pairs • 1st-22nd pairs are called Autosomes

or Body Chromosomes• The 23rd pair are the Sex

Chromosomes because they determine an individuals’ sex

XX= Normal FemaleXY = Normal Male

• The Y chromosome is about ½ the size of a X chromosome

• Sex linked genes are located on the X or Y

• Sex linked genes are expressed in males even if they are recessive

Karyotype- a picture of all chromosomes in

pairs

• Scientist photograph chromosomes during Mitosis, cut the pictures, and then pair them to make a Karyotype

Human Karyotype:

Pedigrees• A pedigree is a chart that shows

the relationship within a family• Genetic Counselors analyze these

charts to understand the family’s genotypes

Square = MaleCircle = FemaleHorizontal Line = MarriageVertical Line = OffspringShaded = Has the traitNot Shaded = Does NOT have traitHalf Shaded = Carrier of trait

Human Blood Types

Pheno: Geno:

A IA IA Homo or IA i Hetero

B IB IB Homo or IB i Hetero

AB IA IB Hetero

O i i Homo

1. A can donate to A & AB2. B can donate to B & AB3. AB can ONLY donate to AB4. O can donate to A, B, AB, & O

1. A can receive from A & O2. B can receive from B & O3. AB can receive from A, B, AB, & O4. O can ONLY receive from O

1. AB is called the Universal Acceptor2. O is called the Universal Donor3. Knowing a person’s blood type is

critical because it could be FATAL4. Rh factor named for “rhesus

monkey” the animal in which it was discovered is the (+) & (-) factor.

5. (+) is dominant & (-) is recessive6. (-) can give to (+) 7. (+) can NOT give to (-)

1. Nondisjunction – failure of chromosomes to separate resulting in an extra or deleted chromosome

2. Gene Therapy – When an absent of non-working gene is replaced with a normal healthy gene using Genetic Technology

3. Crossing Over - when chromosomes are paired so tight in Prophase 1 that chromatids exchange info

Cri-du-Chat• Loud shrieking “cry like a cat” (french)• Chromosome 5 missing a section (mutation)• Developmental Delays• Microcephaly (Small Head)

Huntington’s• Dominant Trait• Mental Deterioration (Wasting Away)• Uncontrolled Movements• Appears in Middle Age

Cystic Fibrosis

Caused by recessive allele on Chromosome 7

Sufferers produce a thick, heavy mucus that clogs their lungs and digestive passageways.

Mucus thinners need to be taken daily

Phenylketonuria - PKU• Recessive Trait• Unable to break down phenylalanine

(Aspartame) a amino acid found in many diet foods, diet drinks, & meats

• Consuming these items can cause irreversible brain damage and death to a person who has PKU

Tay-Sachs • Recessive Trait• Affects mostly Jewish people• Lipid (Fat) Buildup in Brain• Mental Deficiency• Blindness • Death in earlychildhood

Sickle Cell Anemia

Autosomal Recessive Genetic disorder found mostly in African Americans.

Characterized by the bent and twisted shape of the red blood cells.

Down SyndromeAKA “Trisomy 21” Characterized by:• Mental

Retardation• Protruding

tongue• Thick short limbs• Large head• Slanted eyes

NONDISJUNCTION

Edwards SyndromeAKA “Trisomy 18” More Severe than Down SyndromeBaby usually naturally aborted before

deliveryNONDISJUNCTION

Klinefelter’s• Males with an extra X chromosome• Male has female characteristics• Lacks facial hair• Sterile – can’t have any children• Karyotype shows XXY on the 23rd

pair.• Male because he has a Y• NONDISJUNCTION

Turner’s• Female who is missing an X

chromosome• Puberty will not be reached, no

breast, no menstrual cycles, sterile• Karyotype show only one X on the

23rd pair• NONDISJUNCTION

Hemophilia• Bleeding disorder where small wounds

won’t stop bleeding.• Swelling in joints• Possible internal bleeding• Patient needs many blood transfusions

and bone marrow donations• Sex linked Recessive

Color Blindness• Unable to distinguish between

colors.• Sex-linked recessive• Mothers are usually carriers and

make their sons colorblind• Take the test to see if you are

colorblind.http://www.toledo-bend.com/colorblind/Ishihara.asp