Genetically Modified Birds
www.iosrjournals.org 17 | Page
polynucleotide chain, rather, it has two complementary chains that are precisely
cross-linked by specific
hydrogen between purine and pyrimidine bases. The number of adenine is also equal to the number of thymine
and the number of cytosine is equal to the number of guanine. Hence, adenine
always pairs with thymine(AT)
and guanine only pairs with cytosine(GC). The result is now a ladder structure. The ladder is twisted into a
double helix with approximately 10 base pairs for each complete turn of the helix. The two DNA strands run in
opposite directions(antiparallel), and the 5‟ end of one strand is opposite the 3‟ end of the other. The two strands
are also complementary i.e. the sequence of bases along one strand specifies the
sequence of bases along the
other strand [3].
However, for any molecule to serve as the genetic material, it must exhibit 4 features. They are;
replication, storage of information, expression of information and variation by mutation. The DNA shows these
features. Hence, it is the genetic material.
Dostları ilə paylaş: