The document summarizes the structure and components of DNA. It discusses that DNA is composed of four nucleotides - adenine, guanine, cytosine, and thymine - connected by phosphodiester bonds to form two polynucleotide chains in a double helix structure. The three main chemical components of DNA are phosphoric acid, deoxyribose sugar, and nitrogenous bases. Recent advances discussed include identifying passenger mutations in cancer genomes and developing a mouse model called Cancer Rainbow to visualize the functional genomics of oncogenic clonal expansion in tissues.

1. Structure Of DNA & Recentadvances in genomes
By Muhammad HabibUllah 2015-ag-7783
Farooq Zahid 2016-ag-9907
Husnain Ali 2016-ag-5273
UAF Sub Campus Depalpur Okara
Bsc Hons. Agri sciences 4th semester Section B
Deoxyribonucleic acid (DNA) is composed of four deoxyribonucleotides,
i. deoxyadenylate (A),
ii. deoxyguany late (G),
iii. deoxycytidylate (C)
iv. thymidylate (T)
To construct a lengthy polypeptide chain, these units are connected by 3′ to 5′
phosphodiesterlinkages. DNA is the genetic substancefound in all creatures, and it
binds with histone protein in chromosomes. The helical helix of DNA is formed by
two polynucleotide chains. Phosphoric acid, deoxyribose sugar, and four different

2. forms ofnitrogenous bases are the major chemical components ofDNA. Phosphoric
acid forms an ester link with sugar, a glycosidic connection between sugar and base,
and a hydrogen bond between bases. These are the fundamental elements that make
up the entire DNA structure. The importance of the nucleotide sequence of DNA
cannot be overstated. The genetic information is encoded in a certain base sequence;
if the base is changed, the information is changed as well.
F. Misher separated DNA from nucleous in 1869, and Altman coined the term
nucleic acid in 1889. The suitable DNA double helix model provided by Watson
and Crick can explain the gene's specificity.

3. DNA's chemical Composition is as follows: There are three primary components in
deoxyribonucleic acid.
1. Phosphoric acid (H3PO4)
2. Pentosesugar
3. Nitrogenous Base
1. Phosphoric acid, like phosphate, is found in nature and forms the backboneof
DNA molecules, with sugar molecules. It connects the nucleotides byforming
an ester phosphatebond between the deoxyribosesugars of two neighbouring
nucleotides. This bond connects the 3prime carbon in one nucleotide to the
5prime carbon in the following nucleotide.

4. 2. Deoxyribose sugar is a pentose sugar with the molecular formula C5H10O4.
Pentosesugar has a pentagonal ring structure with 3 and 5 prime carbonatoms
attached to phosphoric acid and 1 prime carbon atom attached to the base.
3. There are two types of nitrogenous base.
1. Purine
2. pyrimidine
it is completely fabricated of adenine and guanine with two heterocyclic
rings C,H,O, and N atoms.

5. The 1prime C of the ribose sugar joins the base through a glycosidic bond in DNA,
and this molecule is known as nucleoside. The complete compound is called a
nucleotide when 5prime C is connected to phosphoric acid by an ester bond. A
strand is formed when two deoxyribonucleotides are linked by a phosphodiester
link. DNA contains two strands becauseit is a double helix. The other strand runs
in the opposite or antiparallel direction, i.e., if one strand runs from 3 prime to 5
prime end forward, the other runs from 5 prime to 3 prime end backward. A
hydrogen connection between two nitrogenous bases connects the two strands.
Adenine always creates two bonds with thymine, while cytosine always creates
three bonds with the guanine base.
NUCLEOSIDE NUCLEOTIDE

6. Double Helix structure of DNA
The ‘backbones' of DNA molecules are made up of sugar and phosphates in an
alternating pattern. The rungs of the ladder are made up of hydrogen-bonded bases.
Recent advances in genomes

7. There are many recent advances are covered in the genomes. Some important
advances are discussed here….
1. PassengerMutations in More Than 2,500 Cancer Genomes:Overall
MolecularFunctionalImpact and Consequences
In comparison to a homogeneous background expectation, the percentage of
genes in different gene categories influenced by driver (grey band) and
probable passenger (faded yellow band) LoFs (dashed black line). Different
tumor kinds are represented by the data points in the boxplot. A Kolmogorov
Smirnov (KS) testwas used to determine statistical significance between these
percentages for each of the cancer cohorts.
In comparison to a uniform genomic backdrop, heat map demonstrating
enrichment (red color) and depletion (blue color) of motif gain (upper panel)
and loss (bottom panel) events induced by putative passenger mutations for
distinct TFs. The red-hued TFs are well-known cancer genes. The statistical
significance values for several TFs have been given.
Gain (positive alteration bias) and loss (negative alteration bias) of motif
events found across ETS TF-regulated target genes (on the x axis). The green
triangle represents pan-cancer alteration bias, while the coloured circles
represent alteration bias for distinct cancer cohorts. The frequency of motif-
altering occurrences is shown by the size of the circles.
Genes that are differently expressed due to gain of motif events in TFs
belonging to the ETS TF family are shown in a Q-Q plot. (E) The presence of
significant deletions in the germline and somatic tissues that can engulf or
partially erase coding areas and TF binding peaks.

8. 2. A cancer rainbow mouse for visualizing the functional genomics of
oncogenic clonal expansion
Field cancretization is a premalignant process characterized by the
distribution of clones of oncogenic mutations throughout the epithelium. The
processes underlying the rapid spread of oncogenic clones are unknown, and
the timelines ofintestinal field cancretization can be diverse. Forfluorescently
barcoding somatic mutations and immediately observing clonal proliferation
and spread of oncogenes, we use a Cancer rainbow (Crainbow) modelling
system. Crainbow found that ß-catenin (Ctnnb1) mutations in intestinal stem
cells causeextensive oncogeneproliferation during perinatal development but
not in adults. Mutations that damage the stem cell microenvironment
extrinsically, on the other hand, can quickly propagate through the adult gut.