Genetics Part 2: Development

Genetics Part 2: Development

Yesterday I made salad for dinner. It had a nice name - Avocado, Tomato and Mozzarella Pasta Salad. I took the recipe from the website of Tarla Dalal, the famous Indian food writer.

http://www.tarladalal.com/Avocado-Tomato-and-Mozzarella-Pasta-Salad-3276r

I had the right ingredients and followed the instructions. It was fun to cook, and my wife was happy. But I could do it only because I had the recipe.

(Photo courtesy TarlaDalal.com)

Our genes are like recipes. They build our bodies, just the way my salad recipe cooked the dish. The genes build the body one cell at a time.

Our body is made up of cells, there are about 100 trillion (that’s 14 zeroes after 1) cells in our body. We begin life as one cell. Inside this cell is the recipe written on 46 strips of paper called DNA. Arranged as 23 pairs, these strips are called chromosomes, and the instructions in the recipe are called genes.

When the cell divides into two, both cells carry a copy of the recipe. This division continues and new cells get created. New cells are all alike to begin with, but soon turn into different types – blood cells, muscle cells, skin, kidney and so on.

The source of this magic is our recipe. All cells have the same DNA strips, but different genes are ‘turned on’ in different cells, making them special. So if the genes related to skin material are turned on in a cell, that cell becomes a skin cell.

Now we have to understand how complex organs get made from a bunch of cells.

To understand this, you need to remember something you did in your childhood. Did you ever make a paper boat?

(Image courtesy psdgraphics.com)

This boat is made from a sheet of paper, without making a single cut. You can watch lots of tutorials on YouTube on how to make this. I did not have YouTube when I was small, but I learned to make it from my friends.

To make the boat from a sheet of paper, you have to do things like fold the paper, then turn it, bend and again fold and so on. If you look carefully, these steps are nothing but a recipe, and the recipe makes a complex thing like paper boat from a simple sheet of paper. Those of you familiar with origami know that more complicated things can be made with simple sequence of operations.

(Example of origami art, courtesy http://pdxpursuit.wordpress.com)

When such operations are done on strings or sheets of cells, they create organs. The operations have big sounding names, like invagination and neurulation but really they are just folding and turning and bending. Bunches of cells go through these steps, and make the nose and heart and fingers and all other parts of our body. The instructions for the exact steps come from -you guessed it right- the genes, our recipe.

So this is why a child looks like a mixture of its parents. Some parts of the recipe come from the mother and other from the father. But even though the child looks similar to parents, it is not an exact copy. This is easy to understand. Even if you use the same recipe for making Gajar ka Halwa again and again, it is not going to turn out exactly same every time. Similar, but not same. Genes give the instructions, but the actual result also depends upon other factors before and after birth.

So yesterday’s dinner was really awesome! I made a good dish, and also learned some Developmental Biology in the bargain. The only worrying point is, my wife wants me do more of it – cooking of course, not Developmental Biology.

Suggested reading:

1. The Greatest Show On Earth by Richard Dawkins: Read chapter 8: You Did It Yourself In Nine Months.

2. Endless Forms Most Beautiful by Sean Carrol: You will find some great explanation of Animal Architecture in the first three chapters .

Genetics Part 1: Inheritance

Genetics Part 1: Inheritance

The baby is just a few days old. While she plays gleefully, a group of people surround her. They are her uncle and aunties. ‘She looks just like her mother!’ – someone says. ‘But has the eyes of her father’ – says another.

They are all geneticists. Natural, untrained specialists in genetics, like most other people. Even though the science of Genetics is just fifty years old, people have an intuitive knowledge of its principles since thousands of years.

The Baby of Hope: does a three year hold hopes for HIV infected newborns?

Three years ago, somewhere in the Mississippi state of US, a woman was detected to be HIV positive while she was in labor. The baby was born, and there was a 25-30% chance of the baby being HIV positive too.

Dr. Hannah Gay, a pediatric HIV specialist treating the baby, had a difficult choice to make. It takes about six weeks to get confirmed reports of HIV in newborns. Should she start the antiretroviral treatment? This treatment can be toxic, and so is usually given only after confirmation of HIV.

Dr. Gay decided to start the treatment immediately. The baby received aggressive antiretroviral treatment for the next 18 months. Then, the baby stopped coming for the sessions. Dr. Gay assumed the worst. The virus would come back. It was a lost cause.

She was to get a surprise. The baby came back after 5 months. Dr. Gay assumed she would have high virus infection. There was none!
It was magical. Five months after stopping treatment, the baby was HIV free. No treatment was started then.

This find made international news. Dr. Gay and her colleagues were noted by Time magazine in the list of most influential people of 2013.
That was one year ago. The baby is now 3 years old, still off medication and still free of HIV.

Doctors caution against reading too much in the baby’s case, though. It might be a special case. The treatment might not even be responsible for the good result. It is too early to say from one case. In fact a much larger study, funded by US government, is beginning next year to track a number of HIV positive babies.

Let’s watch the developments. This surely holds a ray of hope for all those who are not yet born.

NASA’s (fake) satellite image of India in Diwali

You must have seen it at least once. Maybe you have liked it, or commented 'Wow!'. A beautiful map of India adorned with dazzling colored lights all over it. This is supposed to be India as seen from NASA satellites during Diwali, the festival of lights.

But something is wrong, isn’t it?

The image shows white, blue, green and red lights in DIFFERENT areas. Do you think some areas in India use red lights and some use only green?

This is not Diwali night seen from satellite. It’s an image created by an institute in US to show the population growth in India. The white lights are the areas of dense population before 1992, blue, green and red lights showing areas of growing population in 1992, 1998 and 2003. So these are night images of India taken over years, and processed to create an illustration.

NASA got apparently frustrated and published an actual image of India during Diwali of 2012. It is black and white and looks no different than any other night. All it shows is where the cities are.

You can have a look at this actual image on the NASA site at

http://earthobservatory.nasa.gov/NaturalHazards/view.php

Why not everyone is happy with Mangalyaan

This year’s Diwali lights got more brilliant, when news of the Mangalyaan’s successful launch reached the nation yesterday. Magalyaan, or Mars Orbiter Mission (MOM) was made in fifteen months for a cost of 450 crores. That’s just about the box office collection of Chennai Express, this year’s another spectacular release. ISRO, the Indian space agency got due congratulations.

Mangalyaan will circle around earth till this month end. On December 1, it leaves for the Mars. It will reach near to Mars in September 14. Thereafter, it will circle around Mars to collect important information.

Not everybody is happy though. There are some serious issues that are being raised about this mission, since last August 15 when Prime Minister Manmohan Singh made the declaration. Lets look at some criticism that is being made -

1. The mission is scientifically not significant: ISRO has used a small rocket to launch the vehicle to Mars. The larger rocket called GSLV is not yet ready. Due to this, the actual scientific equipment that the vehicle is carrying is limited to 25 Kg, barely enough for serious observation.

2. India has hurried this launch to beat China: China has beaten India in most of the earlier achievements in space. But China’s own Mars mission failed in 2011, giving India the chance to get ahead. This is the reason for the hurried program.

3. It’s not doing anything new: Six nations have so far sent similar missions and NASA has two vehicles (called Rovers) crawling on the Mars surface. So we will be just repeating what has been already done.

No matter what you think about these points, for ISRO it will be a great accomplishment. It will be doing two things it has never done before:

1. On December 1, 2013, Mangalyaan will leave the earth’s orbit and leave for Mars. ISRO’s vehicles have never left earth’s orbit before.

2. In Sept 14, when it enters Mars orbit, it will have to be slowed down, otherwise it will escape into space. To control the vehicle after 300 days of journey will be a challenge ISRO has never handled.

With bated breath, let’s wait for December 1. Its a difficult phase for any Mars mission. 30 out of 51 Mars bound spacecrafts have so far failed in this phase. Best wishes, ISRO!

Where hormones rule – Part 2: about stress and competition

Can you remember your latest experience of waiting? My fellow Mumbaikars have a rich experience of waiting for the famous local train to arrive or for the traffic to clear. I have myself waited for one and half hour in shining afternoon sun for a friend to turn up. Some of you may also recall waiting for the doctor to come out of the operation theatre and tell how the surgery on your loved one went.

We all know that it is a stressful experience. Waiting for a traffic jam to clear even for ten minutes changes your mental and physical state. You don’t sense most of these changes, though. The blood pressure goes up. Digestion slows down. Immune system starts working at a very low level. Even reproductive system is shut down. The glucose in blood goes up.

What is going on? Waiting is a familiar situation to the brain from Old Times (please read Part 1 of this article about Old Times). Our ancestors waited for hunting, fights with enemies and many other things. Trained for this, your brain is now preparing you for a long period of trouble. All the systems less important in current situation are shutting down. The energy is being diverted to more important systems, like muscles, lungs and heart. But how exactly is the brain achieving this?

Enter Cortisol. A powerful chemical that rules us in periods of stress. We call such chemicals as Hormones. There is a part of our body, called Adrenal Gland, that makes this chemical. Brain orders the gland to make Cortisol. It mixes with blood and makes all necessary changes as the blood circulates through the body.

Small amount of Cortisol produces good effects. It gives you a burst of energy, better vision, memory and hearing, less pain and also a pleasing sensation. This is what the young people experience when they ride their bikes very fast. They are creating controlled stress. They know that they are going to relax in a moment. But when Cortisol remains in blood for a long time, it produces all the harmful effects that we know as stress related problems. They include high blood pressure, diabetes, fragile bones and susceptibility to infections.

Now let’s turn to those Diwali shoppers of Part 1 that you have tagged as successful people. They are under influence of another powerful hormone called Testosterone. This magical chemical is made in the tastes of males and ovaries of females. Testosterone springs into action when brain senses another age old situation – Competition.

All societies that we know have a ladder of social status. We are all aware of our place on the ladder, even though we do not always admit it. Our brain has been trained by the struggle to climb the ladder in Old Times. It knows that going up means a better chance of survival.

The struggle to improve our status brings in competition. Testosterone is brain’s formula for winning. Apart from preparing your body, Testosterone also increases risk taking and confidence in you. It makes you more alert and quick. Many times, these qualities help you to win.

But now Testosterone starts taking you on a ride. We know that brain commands the body through hormones. But it happens the other way round too. With Testosterone in our blood, we become more confident, talk loudly, become more aggressive. The brain tracks all this, and concludes that we are in competition. So it makes even more Testosterone. You are now in a loop.

This is a normal picture of investors when the stock market is going up. Excitement breeds even more excitement. After a while it reaches ridiculous proportions, till the bubble bursts and Cortisol takes us in its arms.

Cortisol has its own loop too, one which is really bad for us. When you are feeling down, your voice lowers, movement slows down, you are less confident. Brain gets these signals, and starts making more Cortisol. This negative loop can have a disastrous effect on your mood, leading to panic attacks.

As a rule, I have stayed away from prescribing any cure. But I want to give one here, something I have practiced. You know that the body sends signals to the brain. You can use this when you feel you are going down the Cortisol spiral. A nice meal, massage, modest exercise can create a feeling of well being and break the negative loop.

When you are anxiously waiting for the train, even smiling to yourself can make a difference. No harm in trying.

Where hormones rule - Part 1: The Old Times

It’s 11’o clock in the night and you are watching Crime Patrol on Television. A particularly gruesome crime is going to take place. You see a man wielding a threatening axe in hand. In a few seconds the axe is going to wreak havoc on the neck of a perfectly innocent family man.

As you watch this, your pupils grow bigger, your blood pressure rises, breath quickens, heart beats faster, a tightness comes in your muscles, blood gets diverted away from your stomach – giving you the butterflies. If someone is watching you now, you are the picture of a person facing danger. You can pounce any time, or run away, as the danger may be.

If you are looking at yourself somehow, you will say – relax, this is just a television show. No one is going to attack you. But the funny part is, you are not even aware of these changes. It is as if your mind and body are on an autopilot.

Before we start understanding why this happens, let me show you a small bit of our history. I will draw a timeline:

- Women started working in factories and offices – Less than 100 years ago

- Men started working in factories and offices – Less than 500 years ago

- Men started working on farms, women cook and take care of children – 7000 years ago

- Men hunt and women take care of children – since more than 1 lac years ago

As you can see, our history is made up of men hunting and women tending to children. There was hardly any cooking. There were no fixed houses, no villages and cities. We were all wandering tribes. Our bodies and minds are shaped in these conditions. Scientists call this as ‘Ancestral Environment’. Let’s us call it, simply, ‘Old Times’.

While trying to understand ourselves and others, the biggest mistake we can do is to think in light of today’s conditions. Our brains are made in Old Times. So when you fight with our office colleague today, your brain thinks of him as a member of another tribe. When you watch terrible crimes or sensational news on television, your brain takes it as an actual danger, not just a moving image.

Well, there is a part of mind that can think and understand this. This is why one part of you is definitely aware that it’s just an office colleague. But there is another part of mind, that is hidden. It is this part that controls the emotions, feelings and bodily reactions. This part is far more powerful than the thinking one. And it was shaped in the Old Times.

In the Old Times, there were very few things that mattered for survival. Danger from enemy like predator or other humans, opportunity to get food, opportunity to find mates and protecting children. Any man or woman who could do these things well, survived. There were no projects to be planned or diplomatic emails to be written.

These critical situations had to be identified quickly. There was no chance of second thought. Imagine one of our ancient forefather standing in the wild. There is a rustle in the leaves. He has to choice but to conclude quickly that it’s a poisonous snake. Thus the brain learned to detect all important situations fast, even if wrongly sometimes.

Now let’s get back to you watching Crime Patrol. Brain detects danger as per Old Times. Facing danger needs speed, strength and alertness. Brain prepares the body accordingly. The pupils dilate to take more light in. The body needs more oxygen, so the breath quickens. Muscles like legs, arms and organs like heart, lungs get more blood. Unknowingly, you become like your ancestor who has just detected a snake in the leaves.

Can you spot successful people in the Diwali shopping crowd? They will be walking straight, heads high, speaking loudly and aggressively. We have taken the first step in understanding them. We have learned that our mind was shaped in Old Times. We need to know a few more interesting facts. This is where the hormones come in. But that has to wait for Part 2.