(1843-1915) 1. used special staining and called the chromosomes he saw chromatin.

2. Sawthat cells divided Longitudinally

3. coined the term "Mitosis"

(1846-1910)

made observations about Mitosis

1. fertilized egg has equal contributions from both parents

2. divides longitudinally each daughter cell gets = # of chromosomes

3. saw cells have 2 chromosomes from each parent combine and produce 2 daughter cells with 4 chromosomes

(1849-1922)

described the reduction division of meiosis by showing the polar bodies in the egg and 4 sperm

(1834-1914)

believed that chromosomes doubled before meiosis and that 2 divisions are required to reduce the chromosome # so that it can be restored at fertilization

1950s

1. proposed contractile ring theory

2. Actin filaments align around the cell near the surface and interdispersed w/the actin is myosin.

3. Mechanism is similar to the sliding filaments of skeletal muscle contraction

(1733-1806)

showed that both parents contribute to offspring

1866 and 1872

noted segregation in experiments w/ peas

“I have noticed that a cross between a round white and a blue wrinkled pea, will in the third and fourth generations at times bring forth blue round, blue wrinkled, white round, and white wrinkled peas in the same pod, that when the white round seeds are sown again, will produce only white round seeds…the blue wrinkled peas will bear only blue wrinkled                 seeds.”

(1759-1838)

1. first to study peas

2. found that gray seed color dominated white seed color

3. crossed white/gray which produced both gray and white

4. Did NOT determine ratios betweeen crosses

5. Concluded that offspring take on the traits on one or the other parent

(1772-1850)

Conclusions of his experiments

1. same hybrids are always formed when crossing the same pure types

2. male and females contribute equally

(1866-1945)

1. Studied Drosophilia searching for a new species

2. believed in evolution but rejected the idea beacuse he felt it could not be tested

3. 1910 discovered the white eye mutation with the help of Sturtevant, Bridges, and Muller

4. 1933 Nobel Prize in physiology and Medicine 

(1891-1970)

1. worked with Morgan, Bridges, and Muller to discover the white eyed fly mutation, linkage and mapping

2. education was funded by Morgan

3. in the Morgan laboratory made many contributions to: gene mapping, the production of a diffusible substance by a gene, to name just a few.

(1890-1967)

1. worked with Morgan, Bridges, and Sturtevant to discover the white eyed fly mutation, linkage and mapping

2. joined the Morgan laboratory in 1912.

3. Main contributions were theoretical

4. led to data interpretation and shaped the design of critical experiments that he did not have the time to pursue

5. 1st to use upper case letters for dominant genes and lower case letters for recessive genes