1. Chapter 14-1 Human Heredity

2. Human Chromosomes
A. Karyotype- an arrangement of chromosomes from longest to shortest. Used to determine some genetic disorders.

3. 1. Pictures of chromosomes are taken during metaphase of mitosis.
B. Creating a karyotype
1. Pictures of chromosomes are taken during metaphase of mitosis.
2. The chromosomes are paired up
(23 pairs for humans)
3. The pairs are number 1-23.
a. Pairs #1-22 are called autosomes.
b. Pair #23 are called
sex chromosomes.

4. C. Sex(gender) Chromosomes 1
C. Sex(gender) Chromosomes 1. Determines the biological gender of an individual a. Females =XX. All female gametes (eggs) contain ONE X chromosome. ** Therefore, females can only pass on an X chromosome, for pair #23, to offspring.

5. b. Males= XY. All sperm contain either X or Y
b. Males= XY. All sperm contain either X or Y. Therefore, males pass on either an X or Y to offspring for chromosome pair #23. *This determines the biological sex of offspring.
Father X Y X
X X
X Y
Mother X
X X
X Y

6. II. Human Traits A. Biologists must: 1
II. Human Traits A. Biologists must: 1. Determine if trait is controlled by a single gene 2. Determine that trait is not a result of environment 3. Study inheritance pattern of trait

7. B. Pedigree-Chart used to follow a trait through several generations.1. 2. 3.
**Half shaded circle/square indicates an individual that carries the recessive trait (heterozygous) but does not express the phenotype.
EX. Male Carrier
= Male
=Female
=Child/children
=Marriage
= Affected Male
=Affected Female

8. 4. Roman Numerals=Generation Numbers
5. People are numbered from left to right starting over with 1 for each generation. I.
1 2
II.
III.