Biology 1

Chapter 12

Patterns of Heredity and Human Genetics

I. Dominate Heredity

a _________ allele will cause a person to __________ the dominate trait

(Curling tongue, free- hanging earlobes)

A. Huntington’s Disease

1. __________ genetic disorder

2. degeneration of nervous system, uncontrolled jerking movements, mental deterioration

3. onset between ________ years old

4. no treatment

**Why is this disease so difficult to control?**

B. Human Physical Features

1. ________ chin

2. widow’s peak

3. free hanging earlobes

4. ________________ thumb

5. ____________ shaped eyes

6. ____________ lips

7. hairy middle knuckles on fingers

8. tongue curl

II. Recessive Heredity

caused by recessive alleles , may be a __________ with no symptoms, both

alleles must be affected to show full set of symptoms

A. Cystic Fibrosis

1. ____________

2. most common genetic disorder among white Americans

3. 1 in 20 whites are carriers

4. breathing difficult due to thick ___________ built up in lungs

5. digestion difficult

6. onset at birth

7. no cure

8. was an advantage to be a carrier because it made a person dehydration resistant when they came down with Cholera

B. Sickle-Cell Anemia

1. most common among African Americans

2. red blood cells deformity, shaped like half moons; cannot carry correct amount of _______________

3. cause blood clots and damages tissues

4. treatment- blood transfusions

5. no cure

6. onset at birth

7. was an advantage if you were a carrier, then you were immune to malaria

C. Tay- Sachs

1. _________ by age ____

2. most common among Ashkenazic Jews

3. Onset between birth and 8 months

4. Symptoms:

a) loss of movement and mental

b) capabilities

c) blindness

d) no treatment

D. PKU- Phenylketonuria

1. _____ lethal if treated by a special ________

2. Symptoms:

a) possible mental retardation

b) severe damage to central nervous system

3. onset at birth

4. can be detected in fetuses and mother can start on special diet before child is born

III. Multiple Alleles

*3 or more alleles per trait

*increases variety of characteristics that can be shown

Blood Type

1. controlled by molecules on red blood cells

2. A co-dominate to B

3. A and B completely dominate over O

4. type important for blood transfusions, parental disputes, and crimes

IV. Polygenic Inheritence

*many alleles, a wide variation in traits influenced by which alleles are present.

( Skin color, Hair color, eye color)

V. Sex- Linked Traits

*traits carried on ________ chromosomes (23^rd pair- X’s and Y’s)

*if carried on X- males always affected if they receive the affected X

*females can be affected _____ carriers

A. Red- Green Colorblindness

1. cannot tell these two colors apart

2. carried on the X

B. Hemophilla

1. can be lethal if not treated

2. treatment- blood transfusion, injections of clotting factor 8

3. onset at birth

4. free bleeding

5. carried on X

6. inbreeding causes this disease to show up in abundance (Royal Family)

VI. Mistakes in Meiosis

*mistakes in chromosomes, usually caused in crossing over or separation

**(review the types of chromosomal mutations possible)**

VII. Autosomal Aneuploidy

1. having abnormal ____________ of chromosomes (trisomy, monosomy)

2. karyotyping can identify this abnormality

3. Down Syndrome – Trisomy 21 (short in stature)

Who determines the sex of the child? ____________. Why? _______________ __________________________________________________________________

Do you always express a dominant trait? ______. Why? ________________ _________________________________________________________________