Cells and Genes and Traits, oh my! :-)

[bearnybear]

Hi. Each human cell contains the gene for how many traits? I know that a cell has chromosomes, on which there are thousands and thousands of genes. Does this mean thousands and thousands of traits can be inherited by the genes in every cell?

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Merged post follows:

Consecutive posts merged

Never mind. I realized it can be thousands, or more, traits!

 

Sorry, I forgot I had to merge my posts.

Edited April 20, 2009 by bearnybear
Consecutive posts merged.

[lucaspa]

This gets very complicated.

 

First, supposedly each gene codes for one protein. And the human genome has about 30,000 genes. But not all genes are expressed (turned on) in every cell. For instance, the dystrophin gene is only expressed in skeletal muscle cells. Albumin is only expressed in liver cells. Osteocalcin is only expressed in bone forming cells.

 

So, each cell does "inherit" all the genes but does express them all. Depending on what cell type it is -- "phenotype" -- it expresses a subset of genes particular to that phenotype. Plus, many genes are expressed only in embryonic development. However, each cell expresses probably 20,000 genes. Many of them are common to each other, like the genes to break down sugar and get energy.

 

Second, what we call "traits" are often the result of more than one gene. So, being "tall" is the result of many genes in many different cells, but particularly the genes in the growth plates in bones while you are growing up. That a trait is the sum of many genes is called "polygenic". Also, many genes participate in more than one trait. This is called "pleiotrophic".

 

Third, many traits are also influenced by DNA that doesn't code for proteins. Some of this DNA is in the region that controls whether the gene is expressed or not. During embryonic development, this region is very important because how tall we are, for instance, partly depends on how long the IGF gene is turned on.

 

Some DNA makes RNA, which in turn controls when genes are turned on or off. A recent article in Scientific American says that a major difference between humans and chimps is the HAR1 region. It encodes for an RNA but it appears to control the development of the brain -- particularly how wrinkled the surface of the brain is.

 

So, bottom line: each cell expresses probably about 20,000 proteins but those proteins vary a bit depending on what the cell is. But "traits" are a bit different and I don't think anyone has numbered the "traits" in a human being.

[jake.com]

Hi. Each human cell contains the gene for how many traits? I know that a cell has chromosomes, on which there are thousands and thousands of genes. Does this mean thousands and thousands of traits can be inherited by the genes in every cell?

---

Merged post follows:

Consecutive posts merged

Never mind. I realized it can be thousands, or more, traits!

 

Sorry, I forgot I had to merge my posts.

 

This is a genome map for chromosome 3

 

This shows how detailed a chromosome is for programming you. While a number of certain traits is impossible to determine, it's easy to guess that there are more than a few.

 

Also, heres a map of the chromosomes that make up a human genome. This one is diagrammed to show all gene entries and QTL that have shown associations or linkages with exercise-related phenotypes. This shows how many phenotypes are related to one general trait. Seeing how there are hundreds of traits to choose from, an simple estimate shows that there must be thousands of traits in one gene.