Hammerling`s Discoveries

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Transcript Hammerling`s Discoveries

Joachim Hämmerling

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Joachim August Wilhelm Hämmerling (March 9, 1901 - August 5, 1980) was a pioneering Danish-German biologist born March 9, 1901 in Berlin.

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He was educated at the Berlin and University of Marburg.

University of

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He received his doctorate in 1924.

Prior Knowledge

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Friedrich Miescher discovered large quantities of material in the nuclei of cells, which, contrary to popular belief during those times, did not function like proteins.

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Miescher named the newly discovered material nuclein because of its location in the nucleus. It later became known as DNA.

The Experiment

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Hämmerling Acetabularia, a type of green algae, in the laboratories in the 1930s.

began growing

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He discovered that the plant had one cell and the nucleus was always located in the rhizoid. He began studying the roles of the nucleus and cytoplasm by experimenting with the

Acetabularia.

The Experiment Cont’d.

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To make sure the genetic traits were plant.

not distributed all throughout the cell, he merely cut the cells in half to see which part could regenerate into a new

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The heads of the algae withered when detached, and only the feet regenerated. Hence, he believed that the traits were somewhere stored in the feet of these algae.

The Experiment Cont’d.

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He wanted to switch the top halves of each alga with the feet of the other.

In order to make sure that his idea had a chance of working, he performed a control experiment.

He snipped off the top of a cell and then tried grafting it back onto its base, which worked.

This showed that the traits for each species resided in their feet.

The Experiment Cont’d.

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He transplanted the algae by switching the top halves.

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He watched the plants carefully, and he saw that after switching, no parts of the morphological withered, but over time the top halves slowly changed into the form that was dictated by the "traits'" instructions in the respective bases.

hybrids

The Experiment Cont’d

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To make sure he was right, he viewed the feet of the plants with a microscope to make sure that they contained nuclei, and they did.

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Hence, nucleus.

Hämmerling concluded that the genes of the plants resided in the

Conclusion

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This experiment demonstrated that the nucleus contains the genetic information, DNA, and controls development. The experiment also proved the existence of morphogenetic substances, which would eventually become known as mRNP.

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Because of his work with Acetabularia, when a new species of the plant was discovered in the Pacific Ocean in the 1970s, it was named after Acetabularia haemmerling after him.

References

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Wikipedia. (2011, September 29th). Joachim Hämmerling. Retrieved from http://en.wikipedia.org/wiki/Joachim_Hämmerling

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Hämmerling's acetabularia . (n.d.). Retrieved from http://www.science-projects.com/Acetabularia.htm

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Molecular genetics: Genetic history. (n.d.). Retrieved from http://genetics.bizhosting.com/history.html