Blog 1: Past biologists and their contributions to biology

1. Greg Mendel (1822-1884)

Mendel was an Austrian Monk and Biologist. It was in late 19th century, that Mendel brought together his ideas which revolutionized the world of biology. Today he's generally known as the father of genetics, although his work was only recognized decades after his death.

Mendel's big contribution to genetics come from his in depth studies of common pea plants. He picked pea plants because they can be grown easily in large numbers, showed distinctive traits and their reproduction can be manipulated. Because pea plants have both male and female reproductive organs, Mendel was able to develop two important principles from the self pollination and cross pollination of these plants.

Mendel's two principles:

Principle of segregation: for any particular trait, the pair of alleles of each parent separate and only one allele passes from each parent on to an offspring.  Which allele in a parent's pair of alleles is inherited is a matter of chance.

Principle of independent assortment: different pairs of alleles are passed to offspring independently of each other. The result is new combinations of genes from the random assortment of the alleles.

Rosalind Franklin (1920 – 1958) Even at a young age, Franklin excelled at science, and unlike other women at the time, she dreamed of a leading a life as a scientist. Passing away at 37 because of ovarian cancer, Franklin’s led a life full of controversy surrounding her work. Franklin’s contribution to biology lies in her research and discovery work that led to the understanding of the structure of deoxyribonucleic acid, DNA. Although Franklin herself did not solve the DNA structure, her X-ray photographs of DNA were the key for determining the solution. When Watson saw Franklin’s crystallographic portraits of DNA, the structure of double helix became apparent to him. Even though Watson and Crick won the Nobel prize for the discovery of the Double Helix, Franklin's contribution to the cause was immeasurable. Frederick Sanger (1918 to present) Frederick Sanger is a biochemist, and a two-time Nobel Prize receiver. Sanger was a brilliant scientist, and his contribution to both fields of biology and chemistry is boundless. In 1980, Sanger and his colleague Walter Gilbert shared half of the Nobel prize for chemistry for their work concerning the determination of base sequences in nucleic acids, which as we know today, has become a powerful tool in biology. The key to Sanger’s method of base sequencing is that all reactions start from the same nucleotide and with a specific base. Thus in a solution where the same chain of DNA is being synthesized over and over again, the new chain will terminate at all positions where the nucleotide has the potential to be added because of the integration of the dideoxynucleotides. Sanger method of sequencing has provided the backbone technology for DNA sequencing for the last 40 years. Today, the advancement in technology has enhanced Sanger’s method, but is still based on the same principles.  Barbara Mclintock (1902 – 1992) Barbara McClintock pioneered the study of cytogenetic at Cornell University —a new field in the 1930s. She was a brilliant scientist, often which distant herself from her male colleagues.   She made her notorious contributions in biology from her study of maize – discovering TE (transposable elements). McClintock’s innovative cytological techniques laid the groundwork for her career, which determined the evidence of genetic crossing over, cytological determination of the location of genes within chromosomes, identification of the genetic consequences of nonhomologous pairing, and etc. Published in 1948, her biggest finding was that the chromosome-breaking locus did something hitherto unknown for any genetic locus: it moved from one chromosomal location to another, a phenomenon she called transposition. Years after McClintock’s dicovery, scientists were finally able to study both TEs in much more molecular detail. Arthur Kornberg (1918 –2007) Kornberg was an American biologist who studied enzymes and DNA synthesis. He worked at various universities, but he was devoted to enzyme and protein biochemistry. After decades of isolating and purifying the enzymes of the cell, He and Severo Ochoa identified the enzymes catalyzing the synthesis of DNA, polymerase I. This, being his most significant contribution to biology, won Kornberg and Ochoa the Nobel Prize in 1959.