Re: genetic mutations

[Guest guest]

My mom and her four siblings are affected by a chromosome defect. Interestinly, most of my cousins (on my mom's side) have picked microbiology as their profession. This is all we talk about when we meet.

Here is how we have explained this to the older kids when they begin to ask questions:

"Chromosomes are kinda like two trees ('cos chromosomes come in pairs). The branches on the trees as the genes, and the leaves are the DNA. Mutations can change the way the leaves are, and it can also change half the tree. A tree with different leaves look a bit different from other trees, and trees with a different "top" or "bottom" look very different from other trees. Some families have huge yards with many different trees and others have just a few.

Some trees grow up looking different from the start. Other trees look ordinary until there is something harmful in the soil or in the air. Poison in the soil or in the air can damage the leaves and harm the tree. Trees with a different look are just as precious as those who look ordinary".

Mutations can take place in several ways:

It can take place in an egg cell or a sperm cell, and once the two cells come together (at fertilization) the mutation is done. The new fetus now has a gene mutation. There!! The DNA has been permanently changed. The baby has inheritated it from his parent. The mutation will be part of the child's life forever...

The DNA can also be changed in one single cell after fertilization as the cells keep dividing. Some of the changes in he DNA does not cause problems, but others will affect our health.

The other way a mutation takes place is a change of the DNA caused by the environment. This could be the UV in the sunlight, radiation etc. but this can't be "passed on". If my DNA is changed due to radiation, I can't pass it on to my offspring.

Liz

To: sList Sent: Sun, June 13, 2010 11:44:39 AMSubject: RE: Re:: Big study identifies new genes that may be involved in autism

Diane, I always thought they were the same. What fascinates me about psychological labels is that it displays a percentage. If a person has a certain psychological condition there is a higher chance a sibling will also develop the problem than the general public. And the percentage goes even higher for identical twins. But how do you explain those people in those groups who do not develop the problem.

I don't think genetics can explain how fast the numbers have grown. If we really didn't fully understand the problem before and we placed all those people into institutions that means there should be a large decrease in institutionalized adults. And speaking of adults, where are they?

From: sList@ yahoogroups. com [mailto:sList @yahoogroups. com] On Behalf Of Diane RosensteinSent: Sunday, June 13, 2010 1:22 AMTo: sList@ yahoogroups. comSubject: Re:: Big study identifies new genes that may be involved in autism

What I found most interesting in the blurb about the study was that there were some children who had gene (alterations or deletions) that their parents DID NOT have.

I've always assumed that "genetic" was the same as "inherited". Obviously, this is not true.

(I also wondered how they fit just under 7 generations into just 30 years with 100% inheritance rate too whenever I heard "autism is genetic"; that is 1 in 10,000 to 1 in 91 in just 30 years!)

Did anyone else think that "autism is genetic" meant "passed down from the parent" also?