The Nucleobases Etymology

Albrecht Kossel (left) and a thymus histological section (right)

Adenine, thymine, cytosine and guanine are nucleobases used in forming nucleotides of the nucleic acids. The purine nucleobases (A and G) bind to the pirimidinic ones (C and T) via hidrogen bonds in the DNA. 

Albrecht Kossel (1953-1927), was a German biochemist who isolated and described the nucleobases and named them with the names we currently use.

The end of the Romanovs

After the success of the Bolshevik Revolution, the Tsar Nicholas II of Russia abdicated in 1917. He and his family were taken to Yekaterinburg, where they were kept as prisoners and finally executed under direct orders of Lenin in 1918. Their bodies were buried in a mass grave and forgotten for decades.

Romanov's family. Picture from www.historyandwomen.com

The Puffin's Lair - Tamed foxes in Russia

There are two kinds of people in the world: those who love dogs and those who prefer cats. Until now.

Russian scientist Dmitri Konstantinovich Belyaev strongly believed that foxes can become the new human's best friend. He and his team spent more than 50 years trying to domesticate silver foxes, a melanistic form of the red fox -Vulpes vulpes.
The experiments began in the Soviet Union in 1959 and continue until today, carried out in the institute of Cytology and Genetics at Novosibirsk, Russia.

Epigenetics

As explained in the post About cloning..., when we talked about "surrounding DNA stuff", we were talking about epigenetics.

Epigenetics is the study of changes in gene expression caused by mechanisms in the underlying DNA sequence, some of which are inheritable. In other words, we do not depend only on our genetic code plus the environment to be as we are, we have our "genetic environment" inside that makes us different.

Differentiation process. Picture from www.systembio.com

About cloning...

I am sure that all of you have heard about cloning before. Despite of being a scientific invention or discovery, it has existed from long time ago in nature. It is also called asexual reproduction. It happens, for example, in bacteria. But it also happens in higher animals. 

Example of fragmentation in a starfish. Picture from blocs.xtec.cat

Cloning is an identical copy of an individual, organism or cell that already exists. 

But coming back to more human concepts, cloning has been one of the most interesting issues in science since the discovery of the DNA. The idea of creating a new individual with exactly the same genome as another... it almost means immortality. But we can discuss about philosophical meanings later.

Picture from www.neatoshop.com

Genetic engineering

What do we think when we hear “genetic engineering”? I was used to think in fluorescent animals, giant vegetables and the Ninja Turtles (I haven’t lost hope). But I was pretty surprised when I discover the real meaning.

As a definition, genetic engineering is the modification/manipulation of an organism genome using different molecular techniques. From that definition, we should go further and think what it really means. We may travel to the 1970’s to see that the first organisms genetically modified were viruses and bacteria. The main aim of these projects, after the great discoveries about the existence and the structure of the DNA, was to know if this DNA was modifiable and if life could survive to these modifications. The process is theoretically simple: we take or create a DNA sequence that we know encodes for a particular gene or group of genes, and we introduce this sequence inside the host cell.

Dolly the sheep. The process of cloning. Picture from www.glogster.com

Slight differences

Let's start with general genetics: "What is DNA and what is for?" and "How could we be apparently so different among us but at the same time the same species?"

For answering the first question we will start with the Central Dogma of Molecular Biology:

The DNA is our particular library, essential for life. We have all the necessary information encoded in a combination of four nucleotides (A, T, G and C). This library has hundreds of books, which we are going to call RNA. We have a lot of different kinds of RNA, which maybe is boring and not what you are looking for at this blog. So let's say that this RNA should be translated into proteins to be useful for a cell. These proteins will work independently or as a subunit of a big complex to make what is required.