sper sa te ajute site-ul, chiar daca este vorba de copaci, nu de oameni
sondă ( sau amorsă) este denumirea dată unei secvenţe scurte de ADN (de regulă de 10-40 nucleotide) care este complementară cu o secvenţă din ADN "ţintă"; prin hibridizare, sonda se cuplează cu secvenţa recunoscută pe baza capacităţii de împerechere a bazelor azotate complementare, respectiv timina se cuplează cu adenina iar guanina cu citozina. Dacă sonda prezintă un capăt 3' liber, ea poate constitui punct de plecare pentru acţiunea unei ADN-polimeraze care va cupla noi nucleotide producând o elongare; în acest caz amorsa se numeşte şi "primer".

Este secventa initiala a unui lant DNA care apoi se multiplica, se copiaza si formeaza lantul.(baza aceea de 4 nucleotide)

Veronica iti pun aici un text care explica.
http://www.accessexcellence.org/AB/IE/PCR_Xeroxing_DNA.html

Uite definitia:
To copy DNA, polymerase requires two other components: a supply of the four nucleotide bases and something called a primer. DNA polymerases, whether from humans, bacteria, or viruses, cannot copy a chain of DNA without a short sequence of nucleotides to "prime" the process, or get it started. So the cell has another enzyme called a primase that actually makes the first few nucleotides of the copy. This stretch of DNA is called a primer. Once the primer is made, the polymerase can take over making the rest of the new chain.

Sper sa-ti fie de folos.

engleză term (edited): primers

Vezi definitie in link: http://www.dictionarybarn.com/DNA-PRIMERS.php

"Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques."

"Another way of copying genes or a specific piece of DNA is the polymerase chain reaction. The name "polymerase" comes from the DNA polymerase; this is the enzyme responsible for copying a cell’s DNA. In this procedure the DNA is heated with both the enzyme DNA polymerase and special "primers." Primers are pieces of nucleic acid – sequences of about 20 bases. "

vezi link: library.thinkquest.org/19697/data/Ovpc6.htm

"Bioinformatics is used in primer design. Primers are short sequences needed to make many copies of (amplify) a piece of DNA as used in PCR (the Polymerase Chain Reaction)."

vezi link: http://bioinformatics.org/faq/