Human Genetics

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Karyotype = picture of chromosomes arranged in pairs & organized by size
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Humans have 46 chromosomes
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2 of these are sex chromosomes
XX = female XY = male
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The other 44 chromosomes are known as autosomes

Failure of chromosomes to separate in meiosis – results in an egg (sperm) with too many or too few
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Down Syndrome (extra #21)
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Klinefelter Syndrome (XXY)
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Turner Syndrome (XO)
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Supermale (XYY)

Trisomy – 3 chromosomes
Monosomy – 1 chromosome

1. A picture of a person's chromosomes is called a _____.
2. In this pictures, chromosomes are arranged in pairs according to their ___________.
3. Humans have ______ pairs of chromosomes.
4. The last set of chromosomes is the _____ chromosomes.
5. Males have what sex chromosomes? ______
6. A person who has an extra chromosome #21 has what disorder? __________
7. If a person has XXY for sex chromosomes, he has what disorder? _________________
8. As a woman gets _______, her risk for having a child with down syndrome increases.
9. A human has 2 sex chromosomes, the other 44 chromosomes are called ______________.
10. When chromosomes fail to separate during meiosis, ___________ has occurred.

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To study inheritance, biologists use pedigree charts o Shows relationships within a family

Not all Human Traits can be traced back to a single gene
Many traits are strongly influenced by environmental factors
(ex: height, weight, personality)

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Our complete set of genetic info
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Includes thousands of genes
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Base sequences of many genes identified

• Genes controlling blood types were
1st genes to be identified
• ABO & Rh blood groups
( + and - )

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Genotype
AA, AO
BB, BO
AB codominant
OO recessive
Blood Type
Type A
Type B
Type AB
(universal recipient)
Type O
(universal donor)

Blood Types Practice
Mom has type A blood (genotype AO), dad has type AB blood. What blood types are possible among their children?
Mom has type B blood (genotype BO), dad has type O blood. What blood types are possible among their children?

Phenylketonuria (PKU)
Tay – Sachs disease
Albinism * all recessive

Sickle-Cell Disease codominant (AA, Aa, aa ) heterozygous is resistant to malaria

Achondroplasia
(dwarfism)
Huntington’s disease
* Both dominant

1. Achondroplasia is another name for ____________
2. What are the four possible blood types? _______
3. Is albinism dominant or recessive? _________
4. If two people are both heterozygous for sickle cell trait, what is the chance they they will have a child with sickle cell disease?
5. If a person with type A blood is married to person with type
O blood, what blood types are possible in their children?
6. The human _______ describes all the genes found in humans.
7. What type of chart is used to study a trait in a family? __