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Asked by daniel96 to Andrew, Ben, Beth, Heather, Louisa on 21 Jun 2010 in Categories: General.
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Andrew McKinley answered on 18 Jun 2010:
I’ve not heard of this I’m afraid – do our biologists know the answers? Is it a suppressed immune system that causes it? some people being sensitive to changes in environment? I don’t know 🙁
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Ben Still answered on 21 Jun 2010:
I am not a biologist. But I would say that even though you are very genetically similar to other family members there are still differences. Differences do not have to be that great to change peoples susceptibility to certain illnesses.
But I think the overriding factor in this case is environmental effect, exposure or lack of to certain things as a young child can hugely effect your immunity to many common illnesses.
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Beth Dyson answered on 21 Jun 2010:
I don’t know why this is true, but I get ill a lot less than my sister, even though we have been brought up in the same environment! It may be that you get exposed to different illnesses at school or work, or that there is something in your genes that makes you more or less susceptible to disease. Even though you share genes within a family, each one of you will be unique, so differences can still be seen!
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Heather McKee answered on 21 Jun 2010:
I have to agree with Ben here, it can be to do with the environment people are exposed to, if one person is in air conditioned spaces, hospitals, commutes regularily or is in contact with a large number of people on a day to day basis i.e in schools etc. they will be exposed to far more potentially harmful bacteria and thus the risk of contracting illness is higher. Other factors that can influence seceptability could be diet, sleep, exercise, stress,smoking, alcohol and even obesity.
Finally some people are just more prone to illness as others, just like every person in your family isnt identical in apperance, genetic make ups differ too thus one family member could get ill more easily than the next. -
Louisa Chard answered on 21 Jun 2010:
Good question Daniel, I don’t think that I really have a full answer for this. You are right that to some extent your immune system is inherited in your genes, but don’t forget we inherit both from our mother and father, and only half of each of their genes, so even if they had a genetically-determined strong immune system, it doesn’t mean we would. Also, immune function is hugely dependent on environmental factors such as what we eat, stress, excercise etc so any differences in these factors between siblings will have an effect on the immune system.
Comments
Ben commented on :
“…may be that you get exposed to different illnesses at school or work…” that is environment!
Ben commented on :
The main point I was trying to make was that the immune system is built up from contracting disease. This is the whole idea behind immunisation. By contracting certain diseases we train our body to battle against others. Some immunisation comes from our mothers in the womb, but a great deal comes from our environment – which diseases we contract.
Take twins. Let one grow up in a perfectly isolated sterile environment, with no foreign bacteria at all. The second should then be allowed to mix with as many other children as possible, play in the dirt and generally have a fun childhood. Aside from the obvious mental differences, you would find that when the adult twins enter the real world the first twin would be sick regularly while the other should find they are sick less often.
This is what I think is the idea behind the book war of the worlds. The invading aliens have developed so much that they have eradicated all known disease and so live in perfectly sterile conditions. So when they invade Earth something as innocent as the common cold can kill them.