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Genes 101 – We are all mutants September 3, 2009

Posted by Geekgirl in Uncategorized.

Yali Xue of Britain’s Wellcome Trust Sanger Institute and her colleagues analyzed Y chromosomes from two men separated by 13 generations, finding four mutations in the 10 million or so nucleotides within that one chromosome. Based on statistics, they estimated that each one of us carries 100 to 200 new mutations in our DNA.

In other words, according to the institute’s news release as well as the BBC’s report on the research, we are all mutants. X-Men (and X-Women), unite!

Today’s post is not about a research article or news. Today’s post is a mini science lesson. WAIT! Don’t go away. I promise, you’ll love it.

A little reminder about the purpose of this blog, especially if you haven’t read that page (psst, go read that page). I hope to contribute, in my own way, to educating people about the real, valid research that is done about LGBT people. If you have ever read NARTH, Focus on the Family or other right wing or religious sources, they will make all sorts of statements that are biased, performed by their own researchers, are not peer reviewed, or come from very old data where the science and analysis was flawed.

One statement I ran across recently is that when the entire Human Genome was sequenced, they did NOT FIND THE GAY GENE.  Well, duh!

This statement speaks volumes about the lack of understanding of “what is a gene?”

So here we go. What is a gene?

A gene is composed of the building blocks  of DNA referred to as bases or nucleotides, abbreviated G, A, T and C. A gene contains many bases and this is referred to as the gene sequence.   DNA is first transcribed into something called messenger RNA. Messenger RNA is then translated into a protein. This translation process, as it is called, is a little bit like a sewing machine. The messenger RNA is threaded through a large organelle inside the cell called a ribosome. The RNA sequence is “read” and the proper amino acid is brought to the ribosome. It takes three bases to code for the proper amino acid.  Then the RNA moves one step and the process repeats. The process stops where there is a special sequence that is essentially a stop sign. Voila, the protein is made.

Amino acids are the building blocks of proteins. Proteins have many roles in our body. They can be part of our cellular structure or they can perform functions. For example, proteins break down the sugar that you eat. This process requires at least 14 proteins. So that makes 14 genes just to chow down the sugar in your coffee. Don’t get me started on what it takes to digest the cream in your coffee. And people are thinking all it will take is one gene to be gay? Maybe. But maybe not.

You can look at the DNA sequence and determine the amino acid sequence of the protein. This is what is known as the Genetic Code.

But….. you CANNOT tell what that protein does by knowing the amino acid sequence! Especially a brand new gene. Sometimes genes are similar, especially between species. So you can guess what that protein will do. But that is only because you can compare it to one that is similar. That also is not considered 100% proof.

So why didn’t they find the gay gene? For the same reason that they did not find the straight gene. First, you need to know what the protein does in the body. Second, it can take many genes acting together, at exactly the right time, for a cell to develop properly or for a metabolic pathway to function (like digesting sugar).

In the 1990’s, the big goal was to sequence all the DNA in a human. But this is a little bit like having lots of sheet music but you don’t know what it will sound like until you play it. And it’s one big symphony. Or kind of like having a dictionary. It has all the words but can you predict what Shakespeare wrote from knowing the entire dictionary?

Scientists are working on the next big puzzle. This one is amazing. The goal is to understand everything that happens from the time the sperm fertilizes the egg until we grow to old age. Think about it. Cells first divide and look the same. Then, magically, they turn into different tissues at different times. We continue growing and developing after we are born. This includes our brain. What genes are active in what cells and at what time in our life? Imagine that as a symphony. That’s one big concert hall and the band plays for a good 80 to 100 years.

I wish that people  would either take the time to educate themselves about science or be quiet. Ignorance doesn’t always lead to bliss.



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