Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Alleles and Genes
Name: Daulat
Status: Student
Grade:  Other
Location: N/A
Country: United States
Date: May 2005


Question:
Is nucleotide sequence of a particular gene different between individuals of same species.For example is nucleotide sequence of the gene expressing insulin in me different from that of other person.



Replies:
At last it would be grateful, if I am provided with the email address of the volunter scientists replying the question, so that we can interact in future too.

For most genes, there is variability among individuals. Each different variant is known as an allele. For the most part, the differences are minor and many of them make no difference whatsoever. There are some genes which appear to be identical or nearly so in everybody examined. These genes are said to be highly conserved. A simple way of looking at it: each individual in a species has the same genes, but different combinations of alleles for those genes.

C. Perkins


It depends on the protein and also the part of the protein. In beta hemoglobin, one of the chains of the protein that carries oxygen, the cause of sickle hemoglobin is a one letter change. The amino acids in a protein chain fold into a 3 dimensional shape which determines what they do. A common analogy for the way proteins and their substrates act is a lock and key. They are shaped opposite each other. But not all of the parts of the key are necessary to its function. The "handle" of the key isn't as important as the shape of the part that fits in the lock. In a protein, the part that is really important is the part that fits with its substrate. In an enzyme, this is called the active site. So, the amino acids that form the active site need to be the same for everyone for the enzyme (or hormone, etc.) to work properly. Amino acids are coded for by DNA, so the DNA sequence that codes for the active site should be the same. However, recall that there can be more than one code for an amino acid, ie. a letter can change and it might still code for the same amino acid. The DNA that codes for the parts that don't form the active parts can be different for each person and not affect the way the protein works.

vanhoeck



Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory