Download Joachim Hämmerling

Joachim Hämmerling
0 Joachim August Wilhelm Hämmerling (March 9, 1901
- August 5, 1980) was a pioneering Danish-German
biologist born March 9, 1901 in Berlin.
0 He
was educated at the University of
Berlin and University of Marburg.
0 He received his doctorate in 1924.
Prior Knowledge
0 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.
0 Miescher named the newly discovered material
nuclein because of its location in the nucleus. It later
became known as DNA.
The Experiment
0 Hämmerling
began growing
Acetabularia, a type of green
algae, in the laboratories in the
1930s.
0 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.
0 To make sure the genetic traits
were
not
distributed
all
throughout the cell, he merely
cut the cells in half to see which
part could regenerate into a new
plant.
0 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.
0 He wanted to switch the top
halves of each alga with the feet
of the other.
0 In order to make sure that his
idea had a chance of working,
he performed a control
experiment.
0 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.
0 He transplanted the algae by
switching the top halves.
0 He
watched the plants
carefully, and he saw that after
switching, no parts of the
morphological
hybrids
withered, but over time the
top halves slowly changed into
the form that was dictated by
the "traits'" instructions in the
respective bases.
The Experiment Cont’d
0 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.
0 Hence,
Hämmerling
concluded that the genes of
the plants resided in the
nucleus.
Conclusion
0 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.
0 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
0 Wikipedia. (2011, September 29th). Joachim
Hämmerling. Retrieved from
http://en.wikipedia.org/wiki/Joachim_Hämmerling
0 Hämmerling's acetabularia . (n.d.). Retrieved from
http://www.science-projects.com/Acetabularia.htm
0 Molecular genetics: Genetic history. (n.d.). Retrieved
from http://genetics.bizhosting.com/history.html