Some Qs. people asked me on science and my replies to them - Part 34

                                                                        Interactive Science Series 

 

Q: Do all the cells in our body have the same DNA we inherited from our parents?

Krishna: You will be surprised by this answer of mine: NO!

Earlier scientists thought that—although every cell in the body contains its own DNA—the genetic instructions in each cell nucleus are identical. But new research has now proved this assumption wrong. There are actually several sources of spontaneous mutation (the changing of the structure of a gene, resulting in a variant form which may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes) in somatic (nonsex) cells, resulting in every individual containing a multitude of genomes—a situation researchers term somatic mosaicism. Previously we were taught that every cell has the same DNA, but that's not true. There are reasons to think somatic mosaicism may be particularly important in the brain, not least because neural genes are very active (1).

Somatic mosaicism refers to the occurrence of two genetically distinct populations of cells within a single individual, derived from a post zygotic mutation (A zygote is an eukaryotic cell - a  cell  containing a nucleus surrounded by a membrane and whose DNA is bound together by proteins (histones) into chromosomes - formed by a fertilization event between two gametes like ovum and sperm). In contrast to inherited mutations, somatic mosaic mutations may affect only a portion of the body and are not transmitted to progeny. These mutations affect varying genomic sizes ranging from single nucleotides to entire chromosomes and have been implicated in disease, most prominently cancer. 

The mixture of mutation-positive cells with non-mutated cells results in an individual who is a mosaic, or contains different DNA within different cells of his or her body. Mosaic mutations may be present in the germline or soma. Mosaicism can exist in both somatic cells and germ line cells; however, the distinction between germ line mosaicism and somatic mosaicism can be somewhat tricky. As their names imply, somatic and germ line mosaicism refer to the presence of genetically distinct groups of cells within somatic and germ line tissues, respectively. ; However, typically only mutations in the soma have phenotypic consequences or are detectable by current genotyping methods. Mosaic mutations in germ cells are usually only discovered when they lead to inherited conditions in multiple progeny.

Mosaicism is quite common than we think. According to one report (2),  there may be hundreds of changes in single letters of genetic code (single nucleotide variants, or SNVs) in each neuron in mouse brains. Another study (3) found over a thousand in human neurons. These findings suggest somatic mosaicism is the rule, not the exception, with every neuron potentially having a different genome than those to which it is connected. A primary cause of somatic mutations has to do with errors during the DNA replication that occurs when cells divide—neural progenitor cells undergo tens of billions of cell divisions during brain development, proliferating rapidly to produce the 80 billion neurons in a mature brain. They can also occur from DNA damage combined with imperfect repair machinery. Complex genomic rearrangements occur somatically (as well as in the germline). The loss or gain of entire chromosomes is thought to be caused by errors in chromosomal segregation during anaphase of cell division, while non-allelic homologous recombination may cause the loss, gain, or rearrangement of large genomic regions. The image of each cell carrying a carbon copy of the genetic material of all other cells is starting to fade now.

Genetic sequencing does not normally capture the somatic mutations in each cell. You get a sort of average of the person's genome, but that doesn’t take into account any brain-specific mutations that might be in that person.These mutations, scientists think, result in neuro-psychiatric disorders. Somatic mosaicism may also contribute to neural diversity in general. It might explain why everybody’s different—it’s not all about the environment or genome.

Epigenome is environmentally driven modifications of DNA that influence gene activity without changing the genetic code.

If the event leading to mosaicism occurs during development, it is possible that both somatic and germ line cells will become mosaic. In this case, both somatic and germ line tissue populations would be affected, and an individual could transmit the mosaic genotype to his or her offspring. Conversely, if the triggering event occurs later in life, it could affect either a germ line or a somatic cell population. If the mosaicism occurs only in a somatic cell population, the phenotypic effect will depend on the extent of the mosaic cell population; however, there would be no risk of passing on the mosaic genotype to offspring. On the other hand, if the mosaicism occurs only in a germ line cell population, the individual would be unaffected, but his or her offspring could be affected.

Q: What is meta-analysis?

Krishna: Meta-analysis is a calculation that combines data from different studies to come up with a wide-angle view. Scientists also obtain results by using systematic reviews, which compare the bottom line of different studies to determine where the true impact probably lies. Done well, these methods of blending data can provide a result with strong statistical power, finding an effect that might be missed in a single study.

Q: Is white rice bad?

Krishna: If I say that depends on who is consuming it?! :)

White rice is bad some people say. But some experts disagree! Why?

People who do hard work like sport persons need white rice more than brown rice. Like wise older people whose digestion is not up to the mark can benefit more from white rice.

Wise athletes and lifters recognize the high glycemic value of white rice to provide quick fuel for hard workouts and facilitate muscle recovery. Unlike brown rice, white rice does not come with negative drawbacks of gastrointestinal (GI)  issues, allergy symptoms, and blocking the ability to absorb micro-nutrients.

Brown rice and other whole grains contain phytic acid (phytate). Phytic acid is an anti-nutrient binding to essential minerals like iron, zinc, calcium and magnesium preventing our body from absorbing them. It makes digestion much more difficult for already suffering old people.

Phytic acid is located in the bran of the grain. The milling process used to change brown rice to white rice removes the phytate. This is probably one of the only times where refining a food potentially has a positive value. This is especially beneficial for carb hungry lifters wanting to refuel without stomach upset.

Brown rice has more fiber and those lifters suffering from food sensitivity may have an issue with the whole grain. Phytates have antioxidant benefits.

Although white rice is a great alternative for lifters and athletes, it may not be the best option for sedentary people. Also, those training less than 4-days per week or suffering from a metabolic disease, brown rice is a better choice.

Brown rice is a healthy nutrient dense food. It's recommended for the general population and everyday fitness person tolerating whole grains. Brown rice is a rich source of fiber and nutrients essential to a well-balanced healthy diet. 

Q:If eating white rice daily is unhealthy, how come our Indian ancestors are so healthy though they used to have it daily 3 times?  

Krishna: During ancient times, they used brown rice - not polished to the extent we do now with machines.

Moreover, they worked so hard - there were hardly any gadgets to avoid hard work then - that their blood sugar levels wouldn't have shotten up to the levels we face now.

They didn't eat other refined foods and fast foods which enhanced the sugar levels fast in their blood. They ate other fiber-rich foods along with rice.

Our ancestors didn't have transport facilities like we had and walked long distances.

They didn't have TVs etc. to make them couch potatoes. 

Q: Is refined flour bad for health?

Krishna: This is what recent research says: That depends on what lives in your gut! People’s blood sugar levels respond differently to breads based on mix of microbes.

Averaging results from 20 people who ate white and whole wheat sourdough bread for one week each, researchers found no difference in people’s response to the breads, which includes changes in blood sugar levels. But when researchers examined each person individually, a different pattern emerged. Some people’s blood sugar levels climbed more after eating white bread compared with sourdough bread. For others, the opposite was true, the team reports June 6 in Cell Metabolism.

The results are part of a growing body of evidence that nutrition advice should be personalized. Previous work by the same group at the Weizmann Institute of Science in Rehovot, Israel, showed that different people’s responses to eating a variety of foods vary considerably.  Research with mice also suggested that genetic differences may cause one strain of mouse to gain weight on a diet that helps another strain slim down.

 In the new study, researchers Eran Elinav, Eran Segal and colleagues analyzed the study participants’ genetic makeup along with the mix of microbes in stool samples from each person. The team could predict a participant’s response to the two types of bread based only on which microbes were present in the stool — particularly the amounts of two types of bacteria called Coprobacter fastidiosus and Lachnospiraceae bacterium 3_1_46FAA. The researchers don’t yet know how the bacteria change blood sugar levels(5).

Q: What is 'gravity turn'?

 A gravity turn is a maneuver used to launch a spacecraft  into, or descend from, orbit around a celestial body such as a planet or a moon while using minimum fuel. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory.  In order to escape the surface, a craft must rise faster than gravity pulls it down. In order to maintain a stable orbit, the craft must have enough sideways momentum at a high enough altitude to avoid colliding with any surface features or getting slowed down by the atmosphere, if any. A gravity turn combines these two steps into one maneuver, saving fuel in the process. As a craft starts ascending vertically, it slowly turns to the side until by the end of the turn it points sideways.

This is how it happens: 

Almost all space launch vehicles liftoff from the ground in the vertical direction and continue to orbit along an ascent trajectory that is usually optimized for the conditions in order to maximize performance while maintaining conservative safety margins. The actual shape of the path to orbit is influenced by a number of factors, including winds and the desired payload injection parameters.

However, the ideal trajectory profile is based on reaching orbital speed, altitude and orientation as the upper stage completes its injection burn. In most cases, the trajectory is designed to avoid any aerodynamic side load, i.e., the angle of attack is kept at zero.

Ignoring wind factors, this is achieved through the use of a "gravity" turn or "zero-lift" turn. This is a trajectory optimization technique that uses the transverse component of gravity (that is perpendicular to the launch vehicle's longitudinal axis) to turn the velocity vector as it ascents toward orbit. Control is achieved by carefully changing the pitch orientation of the vehicle during its powered ascent.

The gravity turn offers the advantage of a natural ascent profile without wasting any of the vehicle's propellant. Furthermore, by keeping the angle of attack near zero, transverse aerodynamic stresses are kept to a minimum, allowing a lighter launch vehicle.

At liftoff, the rocket begins its vertical ascent, gaining both speed and altitude. Initially, gravity acts directly against the thrust of the rocket, limiting its vertical acceleration and acting as "gravity drag."

As soon as the vehicle clears any service towers and performs any required roll maneuvers, a "pitchover maneuver" is executed in order to steer the rocket's longitudinal axis toward the downrange direction and to establish the ultimate orbit plane. This maneuver is accomplished by gimbaling the rocket engines slightly to direct some of the thrust to one side, creating a net torque on the vehicle.

Once this is completed, a small part of the gravitational force is directed perpendicular to the longitudinal axis. This is the beginning of the gravity turn. From this point until orbit injection, the transverse gravity component continues to grow and causes the vehicle's velocity vector to rotate toward the horizon as it ascends.

The exact initial pitchover angle depends on the specific launch vehicle and is orbital destination. As soon as the pitchover maneuver is completed, the rocket engines are returned to their non-gimbaled orientation. Note that this small steering maneuver is the only one needed during an ideal ascent in which thrust must be used for the purpose of steering. In reality, wind forces do cause minor gimbal-induced corrections during ascent.

Since all space launch vehicles consist of at least two stages, each stage is fired sequentially, resulting in slight discontinuities in thrust. Therefore, ascent sequences are designed to deal with lower-stage shutdown, separation and upper-stage startup.

An actual ascent sequence involves many events and steps (4).

Q: Do we need marches for science like they are happening in the world right now?

Krishna: People say that this is the golden age of science. But some say this is an illusion as it was simply motivated by the technology and to use the fruits of science while still keeping the scientific thought that forms the foundation of science at bay. That is the biggest irony we are facing in the world today!

We in the scientific community are realizing to our horror how politics, religions, emotions and cultures drive public attitudes toward science. How these things are conditioning and corrupting the minds of people and how some are using these tools to fool the general public.

Scientists and Politicians are two different groups. Politicians have a very different job than scientists. At least ideally, scientists seek only to uncover objective truths about the world. They follow a strict methodology, explicitly meant to filter out values, biases, or preconceptions that might color their research. Politicians, by contrast, must grapple with conflicting values and interests. Adjudicating those disputes is the whole job, and most such disputes can’t be resolved by scientific facts alone. So, not surprisingly, the two communities don’t always see eye to eye.

Politicians are most often hostile toward particular scientific findings or communities that tell them things in conflict with their values and interests. The obvious example is climate change.

Then areas like climate change or stem cell research — conflict sharply with the priorities of industry groups and  social conservatives.  

Many climate scientists believe that if they can just get people to grasp the science of global warming, support for climate action will inevitably follow.

Here in India,  interplay between religion, politics and science has become a nuisance. Some vested interests are trying to interpret everything, including their irrational beliefs, in terms of science. The result is a flourishing arena of pseudo-science! Man on the street doesn't even know the difference between real science and pseudo-science. And thinks his religion and culture are truly based on science! We need a march to fight this pseudo-science now.

 Q: Are ghosts really present and wandering during night? 

Krishna: No! It is just an illusion created by your brain under certain conditions. What are these conditions? Read here: Science and the paranormal

Q: How do people get possessed by ghosts? How can we cure them?

Krishna: Ghost possession is a myth spread by vested interests and the un-informed. A person who is allegedly possessed by a ghost is actually suffering from Psychiatric/Mental disorders. The symptoms of an alleged ghost possessed person are often similar to symptoms of various mental illness such a schizophrenia, hysteria or personality disorders.

You can cure them or at least get them under control by visiting a qualified doctor.

Q: Why is Bill Nye considered a scientist? He holds a BS Mechanical Engineering degree, and suddenly he is qualified to lead the charge for climate science??  

Krishna: Being a scientist is a state of mind, not a profession.

If Bill Nye’s state of mind is scientific , yes, why not?

What is a scientist? It’s not holding a Ph.D. degree in science.

A scientist is a person engaging in a systematic activity to acquire knowledge that describes and predicts the natural world. In a more restricted sense, a scientist may refer to an individual who uses the scientific method. The person may be an expert in one or more areas of science.

Scientist - Wikipedia

Bill Nye got a degree in engineering. That does not make him a scientist.

What makes Bill Nye a scientist is his invention of hydraulic resonance suppressor for Boeing and his several other inventions.

Inventions follow the scientific method, the resulting product is the experimental proof, and expands our knowledge of what is possible and works.

Q: Why do scientists speak with authority? Is science equivalent to authority?

Krishna: Scientific way is the best  while deciding the final word on any issue even though there is no 'last word' in science as it is a never ending process always trying to improve even the latest version of knowledge.

Scientists speak with authority as they have the best version of knowledge in their fields and they have earned it with their hard work using the best methods available. They certainly are more knowledgeable on science issues and their impact on society. If anybody can have the authority on any issue, it is the scientists because their minds are made of knowledge of highest order+critical thinking+best methodology+good judging and filtering ability.

Q: Does India need a march for science?

Krishna: Here in India, interplay between religion, politics and science has become a nuisance. Some vested interests are trying to interpret everything, including their irrational beliefs, in terms of science. The result is a flourishing arena of pseudo-science! Man on the street doesn't even know the difference between real science and pseudo-science. And thinks his religion and culture are truly based on science! We need a march to fight this pseudo-science now.

Q: Why are people so sensitive about scientific theories like evolution and global warming? They rush to defend them like some people do religion.

Krishna: 

 People say that this is the golden age of science. But this is an illusion as it was simply motivated by the technology and to use the fruits of science while still keeping the scientific thought that forms the foundation of science at bay. That is the biggest irony we are facing in the world today!

We in the scientific community are realizing to our horror how politics, religions, emotions and cultures drive public attitudes toward science. How these things are conditioning and corrupting the minds of people and how some are using these tools to fool the general public.

Scientists and Politicians are two different groups. Politicians have a very different job than scientists. At least ideally, scientists seek only to uncover objective truths about the world. They follow a strict methodology, explicitly meant to filter out values, biases, or preconceptions that might color their research. Politicians, by contrast, must grapple with conflicting values and interests. Adjudicating those disputes is the whole job, and most such disputes can’t be resolved by scientific facts alone. So, not surprisingly, the two communities don’t always see eye to eye.

Politicians are most often hostile toward particular scientific findings or communities that tell them things in conflict with their values and interests. The obvious example is climate change.

Then areas like climate change or stem cell research — conflict sharply with the priorities of industry groups and social conservatives.

Many climate scientists believe that if they can just get people to grasp the science of global warming, support for climate action will inevitably follow.

Religious heads think they will lose their grip on people and cannot exploit them any longer if the general public realizes the truth. So it has to be suppressed and false information has to be spread to keep their jobs intact.

Here in India, interplay between religion, politics and science has become a nuisance. Some vested interests are trying to interpret everything, including their irrational beliefs, in terms of science. The result is a flourishing arena of pseudo-science! Man on the street doesn't even know the difference between real science and pseudo-science. And thinks his religion and culture are truly based on science! We need a march to fight this pseudo-science now.

So the message that we need to have decisions being made based on a thoughtful evaluation of evidence, based on true science has to get through.

If you know the truth and still keep quiet when people are being mislead and made to suffer in the process, you are not a good human being and therefore, we have to fight these people who are responsible for societal harm. We cannot allow half of the population on Earth get wiped out if they are mislead into thinking vaccines cause harm - not good. Can we?

Q: Do you believe in aliens or ghosts?

Krishna: I don’t believe in ghosts.

But I can have an informed imagination about aliens.

Both are not the same. Read here why: Baseless beliefs Vs informed imagination (or educated guessing)

Q: Is there a scientific reason behind being barefoot while receiving awards on a stage? I have heard and seen Indians being barefoot when receiving awards from someone on a stage? Is there any scientific reason behind this?  

Krishna: There isn’t any scientific reason behind this fad. Maybe people are just aping the Hollywood celebrities.

Or they might have some supertions about wearing footwear while receiving the awards.

Julia Roberts goes barefoot on stage

Barefoot Awards: Stars Who Kick Off Their Heels on the Stage

Oh, yes, high heals make your feet and back hurt. So some of the female celebrities wanted to go natural.

But you can always wear your normal footwear while receiving the awards.

Q: People of science usually claim that people of faith believe things with no evidence, but don't people of science believe in aliens without evidence?  

Krishna: What we do with regard to aliens is informed imagination or educated guess work, it is not a baseless belief. Get that right.

We know (or at least we think we know) how living beings originated on Earth. We know the factors that are responsible for the origin of life and sustaining it. We know how evolution helped in intelligent beings coming into existence. Based on this information, we can guess how life might originate and evolve on other planets in 'other solar systems' of the universe. We can also imagine how these life forms could evolve into intelligent beings that could travel across the universe or at least communicate with other intelligent life existing in the other parts of the universe. This theory of alien existence is just an imagination or a guess work based on our knowledge about life. Not a 'belief'.

Baseless beliefs Vs informed imagination (or educated guessing)

Q: Is there any benefit to an M.Sc. besides the teaching field?

Krishna: It mainly depends on your subject. In general you can go for research or join any scientific institute to help scientists as research assistant or become a lab technician or become an analyst or join as Project manager or people’s manager or conservator or can enter any other field you are interested in. The fields are limited by only your imagination.

Q: Who is the top scientist in the world now?

Krishna: You cannot pin point anyone person like that. Each scientist contributes in his or her own single way to the knowledge bank. And all knowledge in various fields is interrelated to each other enriching the other ones in turn with its own brilliance.

A person with a broader vision understands this. In my view all knowledge is important and anyone who provides something to it is great. 

Q: Is India lagging in field of science as superstitions prohibit them or superstitions are itself sciences made by our ancestors?

Krishna: There are several reasons for India lagging behind in the field of science. You will find them here: How to make scientific research in India a success story

Superstitions are not science-based, they are based on irrationality which is completely opposite to science. But some people try to authenticate superstitions using pseudo-science. And most men on the street don’t know the difference between science and pseudo-science and think the latter is the former! 

Q: Do proponents of evolution care that most people who accept evolution have no clue or care how most of it works, so that they are basically taking it purely on faith?  

Krishna: Evolution is taught in most of the schools world over. And most of the people who received some sort of science education in schools know how evolution works.

And the media ‘educates’ people in its own way about evolution. So I think anybody who knows something about evolution can assess themselves whether it is true or not or can even test it!

Science doesn’t demand anybody to accept anything on faith.

You can use antibiotics indiscriminately and see how evolution works at microscopic level to make microbes resistant. That is what’s happening all the time all over the world. One should be blind not to notice things that are happening around  each moment of the day!

Q: Scientists look and sound less friendly. This is our observation. Is this true?

Krishna: Not to me! :) I have many scientist friends who I can depend on with absolute trust.

Scientists are assumed  to be not famous for their camaraderie because they are trained to question, criticise and, where needed, contest each other's work. That sounds like unfriendly attitude. But that is what progresses science without a dirty spot.  That is what makes science more perfect in methodology than the ones followed by other fields and people.

Scientists are not unfriendly. They are just fact-friendly!

Q: What is accurate Astrology?

Q: What is scientific astrology?

Krishna: There isn’t anything called ‘accuracy’ or ‘scientific’ in astrology. Read here why:

Debate between scientists and people who practice pseudo-science - ...

Q: What could've possibly led to the Indian courts proclaiming that the practice of astrology is a science? Astrology has been debunked widely and is nothing more than a myth. It has continually failed skeptic inquiries into the subject. No one from the field has been able to provide any evidence for the validity of Astrology; indeed they have failed to meet the 'burden of proof lies with the claimant' requirement of any scientific claim. Even then the Supreme Court of India in 2004 ruled that astrology is an ancient science and even directed Universities to consider if it can be included as a subject of study. More recently the Bombay High Court reaffirmed the SC's stand against a PIL filed against astrology.

 Link: http://timesofindia.indiatimes.c...

What are the factors that could've led the courts to take such a stand in favor of astrology?

Krishna: 

In courts you can argue in any way and win if you are an efficient lawyer!

I want to argue this case from a scientific point of view. And I want neutral judges! This is how I made astrologers silent. There is no science in astrology. Only pseudo-science. And ordinary people ( judges are ordinary if they don’t have real scientific background) cannot differentiate between the two! You need a specialist to explain things like this:

Debate between scientists and people who practice pseudo-science - ...

Can anyone file a case again and invite me to argue it? I am game for it!

Q: Do souls exist scientifically?

Krishna: Read here what scientists think about souls here and then come to a conclusion:

Soul?! What is it according to science and scientists?

Q: How reliable is Hindu astrology (especially Tamil, Jadhagam, & Jothidam) predictions? Rational and scientific views would be very helpful since a life decision depends on it.  

Krishna: Please don’t depend on them for life’s important decisions. Because they will lead you into falsehood and illusions. You asked for scientific views. My article just isn’t a view but based on facts and evidence. Read it here : Debate between scientists and people who practice pseudo-science - ...

(Why Astrology is not a reliable science)

Citations:

1. Intersection of diverse neuronal genomes and neuropsychiatric disease: The Brain Somatic Mosaicism Network :  http://science.sciencemag.org/content/356/6336/eaal1641

2. http://www.cell.com/neuron/fulltext/S0896-6273(16)00097-0?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0896627316000970%3Fshowall%3Dtrue

3. http://science.sciencemag.org/content/350/6256/94

4. http://www.spacedaily.com/reports/Ascent_Trajectories_and_the_Gravi...

5. T. Korem et al. Bread affects clinical parameters and induces gut microbiome-associ.... Cell Metabolism. Vol. 25, June 6, 2017, p. 1. doi:10.1016/j.cmet.2017.05.002.