Nucleotide repeats on DNA

Genetics as it applies to evolution, molecular biology, and medical aspects.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
leanbeans
Garter
Garter
Posts: 3
Joined: Tue Aug 23, 2005 8:59 am

Nucleotide repeats on DNA

Post by leanbeans » Tue Aug 23, 2005 9:06 am

is the nucleotide repeat on one DNA strand of one chromosome the same as the one on the other homologous chromosome in a person?
I know there can be different segment repeats, for eg, there can be 3 nucleotides segment repeats on one DNA strand and 10 on the other. But for each segment, is the nucleotide sequence the same on both chromosomes or different?

thanks!

User avatar
mith
Inland Taipan
Inland Taipan
Posts: 5345
Joined: Thu Jan 20, 2005 8:14 pm
Location: Nashville, TN
Contact:

Post by mith » Tue Aug 23, 2005 12:24 pm

Recall that homologous chromosomes are inherited from the two parents. therefore, there's no reason for them to have any similarities.
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
~Niebuhr

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Tue Aug 23, 2005 5:39 pm

The only case where the nucleotide sequence would be the same for both chromosoms in all pairs would be if you are homozygous for every gene you have.. And if you are a girl... :lol:
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

sdekivit
King Cobra
King Cobra
Posts: 586
Joined: Sat Jul 30, 2005 7:16 pm
Location: holland
Contact:

Post by sdekivit » Tue Aug 23, 2005 6:43 pm

MrMistery wrote:The only case where the nucleotide sequence would be the same for both chromosoms in all pairs would be if you are homozygous for every gene you have.. And if you are a girl... :lol:


but still then mutations can occur.

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Wed Aug 24, 2005 8:53 pm

Indeed... Maybe both alleles will mutate the same way at the same time... The odds of it happening is 1 to a bilion bilions, but it could happen :D
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

User avatar
b_d_41501
King Cobra
King Cobra
Posts: 746
Joined: Mon Apr 25, 2005 9:55 pm
Location: Kentucky
Contact:

Post by b_d_41501 » Thu Aug 25, 2005 6:26 pm

The same exact mutation on two alleles.....................it would be a stretch to even classify this as possible. However, since there is a chance of this occurring (I wish I knew the exact possibility of this, but I don't feel like calculating the number at the moment) it would be possible nonetheless. 1,000,000,000,000+ bonus points to the person who finds this probability!!!
"Take four red capsules, in ten minutes take two more. Help is on the way."
----- Voice from the Medicine Cabinet

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Thu Aug 25, 2005 6:58 pm

IF YOU REALLY NEED TO KNOW
The probability of mutation occuring naturally in one gene is one to 100.000. Since you have 2 alleles the probability of mutation at both alleles at the allele of YOUR choise would be (number of genes)sqweared times 100.000. How many points?
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

User avatar
b_d_41501
King Cobra
King Cobra
Posts: 746
Joined: Mon Apr 25, 2005 9:55 pm
Location: Kentucky
Contact:

Post by b_d_41501 » Thu Aug 25, 2005 7:03 pm

So 1 in 62,500,000,000,000?
"Take four red capsules, in ten minutes take two more. Help is on the way."
----- Voice from the Medicine Cabinet

sdekivit
King Cobra
King Cobra
Posts: 586
Joined: Sat Jul 30, 2005 7:16 pm
Location: holland
Contact:

Post by sdekivit » Thu Aug 25, 2005 7:13 pm

MrMistery wrote:IF YOU REALLY NEED TO KNOW
The probability of mutation occuring naturally in one gene is one to 100.000. Since you have 2 alleles the probability of mutation at both alleles at the allele of YOUR choise would be (number of genes)sqweared times 100.000. How many points?


it depends on what kind of mutation. If it's a mutation where 1 nucleotide is replaced by another, you'll also need to take into account the chance of the other base that gets incorporated.

User avatar
MrMistery
Inland Taipan
Inland Taipan
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)
Contact:

Post by MrMistery » Thu Aug 25, 2005 7:27 pm

That is reallly splitting hears into 100000000000....
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

Post Reply

Who is online

Users browsing this forum: Google [Bot] and 1 guest