Genetics

Shireen Rudina

First: A review of Mendel’s Laws

1. Dominance

2. Law of Segregation- one allele from each parent

3. Law of Independent Assortment- each trait acts independently

Human Mendelian Traits

GENETIC TRAIT DOMINANT RECESSIVE

How about the rest?1. Multiple alleles: blood type

IA Type A blood

IB Type B blood

i Type O blood

IAIA Type A

Ia i Type A

IBIB Type B

IB i Type B

IAIB Type AB

ii Type O blood

Codominance

Question: A mother is Type A, and her child is type O

1. What is the child’s and mother’s phenotype?

2. There are two men claiming to be the father: one is Type B, and the other is Type AB. Which one is the father?

How about the rest?

2. Multiple genes for one trait

Sex Chromosomes: X and Y

Pedigree

• Method of following a trait down generations

Analyzing Pedigrees

Tay-Sachs Disease: Simple genetic trait

Tay-Sachs: A recessive disease

• Nervous system and brain rapidly deteriorate

• Children generally die by age 4

• Carriers are crucial

If daughter A marries someone with the trait, what is the probability that their child will be affected?

?

A

Replication

Materials

Replication process

Semiconservative Replication