[Szymon Sniegula]

Szymon Sniegula  asked the Naked Scientists:
   
Hi Chris,

I've been newbielink:http://www.thenakedscientists.com/HTML/podcasts/ [nonactive] for a while and I have to confirm that you do a great job! 

I am writing to you as a PhD student from Krakow, one of the oldest cities in south Poland. Evolutionary biology is a topic I deal with during the ongoing project. Recently I listened to several podcasts during which people discussed topics about different cancers, their genetic origins, developments, evolutions and treatments. One of the latest issues related to the origin, development and evolution of this disease is a problem of epigenetic inheritance systems (ca. inherited changes in phenotype or gene expression caused by other factors than DNA sequences). It has been empirically proved that epigenetics underlie cancer development among both animals (experiments done on mice) and human. Some scientists say that epigenetics have, at least for some cancers, a greater influence for a disease development than do genes by themselves!!!

 
Kind regards, Szymon (English: Simon) Sniegula



What do you think?

[echochartruse]

Where we live, what we do, eat, think, etc shapes the way our genes behave.
Animals including humans populate the various parts of the world and our genes reflect our adaptation to these environments. We all have genes susceptible to disease, cancer, etc, but it depends on our lifestyle and external influences.

A few wallabies become separated from mainland, continue to reproduce, adapt to the climate, the different type of food etc and then we have a sub species.
Similarly with humans. Example, The Chinese folk have been around for a very long time. They have small communities living in close proximity to each other differing and distinguishable not only by language but also genetically.
The Tibetans adapted to living at high altitude and this is expressed in their genes. Adaptation to our environment causes changes in our genome which can be inherited.

Genetic mutation is disease. Disease is not a positive form of evolution in my mind but may assist evolution, if the disease is survived as most genetic changes happen under stress.

Tassie Devils genes change so they can reproduce at an earlier age due to their contagious cancer, etc.

That's what I think.

[grizelda]

Alternatively, Tassie Devils DNA contains unexpressed genes from an earlier time when they bred at a young age. Devils which express these genes nowadays have a better chance of progressing their DNA into the future. This is a simpler concept than epigenetically creating new genes from scratch.

[echochartruse]

Alternatively, Tassie Devils DNA contains unexpressed genes from an earlier time when they bred at a young age. Devils which express these genes nowadays have a better chance of progressing their DNA into the future. This is a simpler concept than epigenetically creating new genes from scratch.

yes i agree. the genes are turned on and off the same as the Tibetan's ability to breath easy at high altitudes. Their environment causes their unique ability. Same if a Tasmanian lived in Tibet at high altitude for decades, his children's genes would react the same.

I'm not taking about NEW genes.

[grizelda]

I doubt that it works that way; more that a small percentage of the population is always expressing anachronistic genes of some type and only randomly does this prove beneficial to the individual (matches a changed environment) and is passed on to the progeny. The devils being inbred, they are lacking in other genetic historical material and so early breeding is the only resource they have to throw at the problem.

[echochartruse]

I'm not speaking of random genetic mutation.
Not saying their genes are modified or engineered.
The genes that they have are expressed depending on their environment.
Cells that are able to switch the genetic profile due to their environment.

The aim of the research says Gibson, was to examine both populations and determine the effect of "nature, nuture and culture on human physiology".

He says the environment includes "the complex mix of what you eat, how stressed you are and where you live"....

For the study, blood samples were taken from individuals living in both the city and villages....Overall the study found "gene expression differed between the two locations in up to a third of all transcripts".

"The main conclusions showed that, which genes are expressed and how much of each gene is expressed depends primarily on where you live and what lifestyle you live," says Visscher.

http://www.abc.net.au/science/articles/2009/12/07/2760760.htm

Genes are susceptible to environmental factors and as we know breeding early is genetic and gives these animals the change, maybe the only chance for survival.

Who knows what number of people are expressing anachronistic genes of some type at this very moment and who will be expressing them differently after dinner? But I would imagine the way they are expressed is for survival in us all.

[szymon]

"yes i agree. the genes are turned on and off the same as the Tibetan's ability to breath easy at high altitudes."

Genes can be turned on and off ina process of methylation (an epigenetic process though which genes are methylated = turned off). The epimutation can lead to changes in the rate of turning on and off of certain genes that can be later responsible for cancer development. Or alternatively, adaptive epimutations can be fixed though natural selection (Tibetan's ability to breatch easy at high altitudes could be fixed following this process). Other genes can be methylated as well. As epigenetics is sensitive to external environmental changes, the evolution based on epigenetics can be very quick...

regards 

[echochartruse]

Humans have same human genes which by the process of methylation are varied due to our environment starting prior to conception with influences caused by mother nature, father time and choice, which is sometimes seen as randomness.

[Geezer]

Humans have same human genes which by the process of methylation are varied due to our environment starting prior to conception with influences caused by mother nature, father time and choice, which is sometimes seen as randomness.

Echo,

I'm not sure what you mean exactly when you say "sometimes seen as randomness", but it's very well established that ionizing radiation can, and does, randomly alter DNA. There's a fairly comprehensive overview in Wiki on the subject:

http://en.wikipedia.org/wiki/Ionizing_radiation