H. Pylori and the limits of science

Hey you! Yes, you. Welcome again to Genetics and Beyond (@genesandbeyond)! Today, new scientific facts that will make you think and maybe laugh. Or the other way around.

We will talk about the discovery of Helicobacter pylori, previously known as Campylobacter pylori, a gram-negative bacteria found in the stomach and related with several gastrointestinal diseases such as gastritis, gastric and duodenal ulcers and stomach cancer. The name comes from Helico (spiral or helix) bacter (bacteria) for its morphology, and pylori (from pylorus or valve) for its location.

Picture from http://www.medcomic.com/040614.html

The debacle of the Darwin-Wedgwood family

Much is known about Charles Darwin (1809-1882) and his fascinating studies, such as the Origin of the Species (1859) or The Descent of Man, and Selection in Relation to Sex (1871). But, what could you tell me about his family? Did you know that he had ten children? And did you know that he was married with his first cousin? Come with us to discover more about this prodigious man and the old and ugly habit of inbreeding.

Charles Darwin and Emma Wedgwood

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.

Rh factor and Pregnancy

Welcome back to the curious and pragmatic side of the science presented by G&B! Today we want to discuss about something practical as well as essential: how important is our Immune System in relation to the pregnancy process?

Picture from askabiologist.asu.edu

The Puffins's Lair - Sweat of the hippos

The hippopotamus (Hippopotamus amphibius) is a semiaquatic herbivorous mammal from Sub-Saharan Africa, and their name comes from the ancient Greek for river horse. One curious aspect is that, despite their resemblance to pigs, they are closer in terms of evolution to cetaceans, but both groups diverged 55 million years ago.

Edward Jenner and the Vaccine's Discovery

Welcome back to Genetics and Beyond! Today, new curiosities for all public that could make us think that Science is even more interesting than what we thought.

Let's start introducing the case. Imagine you are living at the beginning of the XVIII Century. You are a normal person, with ten normal children living in your house on the countryside. Suddenly, one day one of your kids come home after doing the laundry in the river with high fever and skin rashes. At the beginning, with your short knowledge of medicine, you could think that in few days it will go better, but actually you see that your other kids, your partner and also you start having the same symptoms. Nothing to do.

This was a normal situation that happened in those days. Sometimes, if you were lucky, you could find a country doctor. But it wasn't until the mid Century when one as good as Edward Jenner was born in Berkeley, England.

Smallpox symptoms. Picture by commons.wikimedia.org

After his strong education thanks to his father's position, he became a country doctor with experience in surgery. But in science, a good scientist will not leave a question unanswered, even if it's not from your specialty. And that was what Dr. Jenner did. For several weeks, different women came to him because they were suffering what today is called smallpox. They had skin rashes in their hands, and a mild fever.

Dr. Jenner knew about the symptoms of smallpox, a very common disease in the XVIII Century world. But he saw that the symptoms of all those women were similar, and also milder than the normal disease. So he started investigating about the commons between the ladies, and he realized that all of them were milkers. Also, after some weeks of monitoring, he also realized that none of them caught smallpox again. His first conclusion: These milker ladies had caught the cowpox (same as smallpox but in cows), and after that, never again.

Test for the vaccine experiment. Picture from www.med.umich.edu

So he decided to prove whether his conclusions were right or not, so he took a sample of the virus from the hand of a milker lady and inoculated it into a 8 years old kid (you know, methods of this times). After several weeks suffering fevers and mild skin rashes, the kid was recovered. And then, Edward Jenner inoculated him the human virus of smallpox, to prove if the kid got infected or not. ¿What do you thing was the result? Of course! No disease anymore.

Before finishing, thank you for reading us. This discovery is the one which has saved more lives in the whole human history!

PD: In India or China this method but without injection (eating pushes from other diseased) was done 2.000 years before. Catch the tip!

Is Science changing?

Today, in Genetics and Beyond, we want to move from information to opinion. The question of this post is simple: Is science changing?

Some of you would answer: "Off course, science is always changing!", and you will be right. But now try to make the same question from a kind of philosophical point of view. Science has always been discoveries, innovation, progress and answers. Sometimes more a generator of new questions than of revealing answers. But, instead of that very very brief definition, at the end which is the aim of the science?

Picture from ceruleansanctum.com

Conjoined twins

And after Identical of fraternal twins post, let's go deeper to one of the most intriguing malformations in human beings: the conjoined twins.

The conjoined twins, also known as Siamese twins, are identical twins joined In utero (in the womb). It happens in 1 of 200.000 newborns, mostly in women (75%) and their survival rate is between 5% and 25%.

The name of Siamese twins comes from Chang and Eng Bunker, Thai brothers born in Siam (now Thailand). They travelled with P.T.Barnum circus, and they were joined by a band of flesh, cartilage and their fused livers at the torso. They were not only showed as "monsters", but also as good skilled acrobats and magicians, as well as good in business matters.

Chang and Eng Bunker. Picture from fineartamerica.com

Now we know what conjoined twins are, why does it happen?

Identical or fraternal twins?

They are so similar... but are they really the same? Today we are going to speak about the difference between identical and fraternal twins.

First of all, a twin is one of two offspring in the same pregnancy. The main difference between identical and fraternal twins is that identical twins come from the same zygote that is divided in two different embryos, and fraternal twins come from two different zygotes fertilized by two different sperm cells.

Twin differences. Picture from www.genomesunzipper.org

Ok, until now it seems easy, more or less. But in real life, what can make us differentiate between both types of twins? Here some clues:

The Puffin's Lair - Dont' panic!

Have you ever heard about fainting goats? There are hundreds of videos and jokes about them, but, despite how hillarious these goats can be, a genetic disorder is behind. 

Sicke cell anemia and Malaria

Sickle cell disease (SCD) is a genetic disorder that is characterised by a chronic anaemia occurring almost exclusively in individuals of African descent. Individuals afflicted with SCD are homozygous for a key mutation in haemoglobin, whereas individuals who are heterozygous for this mutation are generally asymptomatic and are said to have sickle cell trait. But, fortunately, individuals carrying just one copy of the sickle mutation were known not to develop sickle cell anemia, leading rather normal lives. It was discovered by Linus Pauling (two-times Nobel laureate).

Example of sicke cell trait. Picture from www.transfusionguidelines.org.uk

The Puffin's Lair - To be pink or not to be

Flamingos are wading birds and belong to the genus Phoenicopterus, which only consists in 6 species all over the world: 4 in the Americas and 2 in the Old World - Europe, Asia and Africa.

They are graceful birds, until 1.40 m height with long legs and long necks. Feet have 4 toes and when flying, both neck and legs are completely straight.

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

Milk and Humans

Hello fellow! Back again with a genetic curiosity. Today, milk will be the main character.

From the beginning, humans and milk have been very related. In addition to the appropriate amounts of carbohydrate, protein and fat, breast milk also provides vitamins, minerals, digestive enzymes and hormones. All what is needed by babies.

Picture from www.myspaceantics.com

The Puffin's Lair - Hot N Cold

There are more than one way to determine the gender in nature. We humans depend on who is the carrier of the Y chromosome - XX female, XY male -. Other species such butterflies or chickens depend on the W chromosome - ZZ male, ZW female. But there is still another surprising possibility: the environmental sex determination.

Temperature plays a key role in a special type of this system, being very common in crocodilians, turtles and other reptiles. This nongenetic way of determine whether an egg develops as male or female occurs after fertilization.

For instance, in some turtle species, like Trachemys, eggs from colder nests result in all males, whereas eggs from warmer nests turn into females. In crocodilian species — the most studied is the American alligator— both low and high temperatures result in females, and intermediate temperatures become males.

Temperature-dependent sex determination in three reptile species: the American alligator (Alligator mississippiensis), the red-eared slider turtle (Trachemys scripta elegans), and the alligator snapping turtle (Macroclemys temminckii). (After Crain and Guillette 1998)