The scientist corner: a deeper look to DNA.
Biography: Gregor Johann Mendel
Johann Mendel was born the 20 of July in 1822. He was the only boy in the family and worked on his family farm with his older sister Veronica and his younger sister Theresia. Mendel took an interest in gardening and beekeeping on the family farm as he grew up.
He went on to the University of Olomouc where he studied many disciplines including Physics and Philosophy. He attended the University from 1840 to 1843 and was forced to take a year off due to illness. In 1843, he followed his calling into the priesthood and entered the Augustinian Abbey of St Thomas in Brno.
Upon entering the Abbey, Johann took the first name Gregor as a symbol of his religious life. Gregor Mendel is most well known for his work with his pea plants in the Abbey gardens. He spent about seven years planting, breeding, and cultivating pea plants in the experimental part of the Abbey garden that was started by the previous Abbot. Through meticulous record keeping, his experiments with pea plants became the basis for modern genetics.
Mendel's first experiments focused on one trait at a time and gathering data on the variations present for several generations. These were called monohybrid experiments. There were a total of seven characteristics he studied in all. His findings showed that there were some variations that were more likely to show up over the other variation. He called the one that seemed to be missing from the first filial generation "recessive" and the other "dominant" since it seemed to hide the other characteristic.
Mendel's work wasn't truly appreciated until the 1900s -- long after his death. Mendel had unknowingly provided the Theory of Evolution with a mechanism for the passing down of traits during natural selection. Mendel did not believe in evolution during his life as a man of strong religious conviction. However, his work has been added together with that of Charles Darwin's to make up the Modern Synthesis of the Theory of Evolution. Much of his early work in Genetics has paved the way for modern scientists working in the field of microevolution.
Article: Britain Set to Approve Technique to Create Babies From 3 People
Summary:
British lawmakers voted earlier this month to allow in vitro creation of babies with the DNA of three people. They are still discussing whether it should be put in practice or not.
This technique could prevent genetic diseases in women with mithocondrial diseases, such as muscular dystrophy, loss of vision or even premature death. By using in vitro creation, the embryo would have nucleous DNA from the child's parents but mithocondrial DNA from a donor.
Despite all this advantages, this situation has lit a fierce debate. There are people who are in favor of allowing it. For example, the Muscular Dystrophy Campaign, highlights the benefits it would provide, but others are not so sure. The Human Genetic Alert, for example, has said that we are crossing an ethical threshold. Its leaders have warned that if we start giving support to this kind of pioneering techniques, we might be tempted to create DNA modified babies in the future, and that wouldn’t be ethical.
STRIKING IMAGE
Dolly was the first domestic sheep to be cloned from an adukt somatic cell using the process of nuclear transfer. The cell used as the donor for the cloning of Dolly was taken from a mammary gland, and the production of a healthy clone therefore proved that a cell taken from a specific part of the body could recreate a whole individual. Dolly was born on 5 July 1996 and had three mothers (one provided the egg, another the DNA and a third carried the cloned embryo to term).
This is the clone process that has been used to create this sheep.
On 14 February 2003, Dolly was euthanaised because she had a progressive lung disease and severe arthritis. Dolly has a life expectancy of around 11 to 12 years, but Dolly lived to be 6.5 years old. After cloning was successfully demonstrated through the production of Dolly, many other large mammals were cloned, including pigs, deer, horses… and more animals.
The 21th of february of 1953 the cientists Linus Pauling and Robert Corey published his theory of ADN.
This theory tells us that in proteins , the α helix is the main cause of secondary structure. It was postulated first by Linus Pauling and Robert Corey. The amino acids in an α helix are arranged in a right-handed helical structure where each amino acid residue corresponds to a 100° turn in the helix.
DISCOVERY:
In the early 1930s, William Astbury showed that there were drastic changes in the X- ray fiber diffraction of moist wool or hair fibers upon significant stretching. The data suggested that the unstretched fibers had a coiled molecular structure with a characteristic repeat of ~5.1 ångströms (0.51 nm).
Astbury initially proposed a kinked-chain structure for the fibers. He later joined other researchers (notably the American chemist Maurice Huggins) in proposing that:
- the unstretched protein molecules formed a helix (which he called the α-form)
- the stretching caused the helix to uncoil, forming an extended state (which he called the β-form).
Although incorrect in their details, Astbury's models of these forms were correct in essence and correspond to modern elements of secondary structure, the α-helix and the β-strand, which were developed by Linus Pauling and Robert Corey in 1951; that paper showed both right-handed and left-handed helixes, although in 1960 the crystal structure of myoglobin showed that the right-handed form is the common one.
Linus Pauing was amazed with the Nobel Price in Chemistry for his theory in 1954.
