5 Famous Geneticists



Gregor Mendel (19th Century)



Gregor Mendel:

• He was born on July 22, 1822, to a family of poor peasants.
• He became a priest in the year 1847.
• Mendel Studied the inheritance of seven pairs of traits in garden pea plants and in their seeds.
• He bred and crossbred thousands of plants and observed the characteristics of each successive generation.
• Mendel found out that each plant receives a pair of genes for one trait; that is one gene from each of its parents.
• He came to the conclusion that the pairs of genes separated randomly when a plant’s gametes were formed.
• Mendelism and the two laws:

1. Law of Segregation: A parent plant hands down only one gene of each pair to its offspring.
2. Law of Independent Assortment: a plant inherits each of its traits independent of other traits.





Rosalind Franklin (1920-1958)

 
Rosalind Franklin:

• She is best known for her work on DNA and her crucial contributions to the solution of the structure of DNA.
• Using X-ray, she was able to take a picture of DNA and that's how scientists discovered the helical shape of this vital molecule.
• After her death, her unpublished hypothesis that TMV RNA is a single-strand helix was confirmed.

James Watson and Francis Crick

James Watson and Francis Crick:

• With the help of Muarice Wilkins and Franklin's photo of DNA; Watson and Crick determined the structure of DNA and won the Noble Prize this discovery.
• They discovered that DNA is a double-helical molecule – a helical structure with two DNA strands.

• This discovery suggested two important facts about genetic inheritance:

1. Genetic information was carried by the sequence of nucleotides on the DNA strands.
2. DNA replication could be achieved if the strands were unwound, with each single strand used as the template for a new strand.

Both of these possibilities turned out to be the case.



Barbara McClintock (1902-1992)



Barbara McClintock:

• McClintock studied chromosomes and how they change during reproduction in maize.
• Using microscopic analysis, she demponstrated many fundamental genetic ideas such as:

1. Genetic recombination
2. Crossing over

• She also discovered Transposition; a theory that explains how genes are responsible for turning physical charactersitics on or off.
• McClintock won the Noble Prize for her discovery that genes are able to change position on chromosomes.



Arthur Kornberg (1928-2007)



Arthur Kornberg:

• He was an American biochemist
• Through his research on enzymes, he was the first to isolate DNA polymerase, the enzyme that assembles DNA from its components, and the first to synthesize DNA in a test tube.
• Kornberg won the Noble Prize for his work in 1959.
• He later became the first to replicate an infective virus DNA in vitro.