GENOMIC VARIATION ,PHYLOGENY AND SYNTENY (GRASS GENOME COMPARISON)

Presented by Ashish sharma

Genomic variation

“Variation”-a change or slight difference in condition, amount, or level, typically within certain limits.

“Genome”-the genome is the genetic material of an organism. It consists of DNA (or RNA in RNA viruses). The genome includes both the genes and the non-coding sequences of the DNA/RNA.

Hence, genomic variation will defined as the slight difference in the

whole Set of the sequence of the genetic material between two

individual beings Of whether same class of organism or in different class

respectively ..

Example – Genomic sequence of human are

approximately 99.99% similar and remaining sequence is dissimilar …

Due to this dissimilarity every individual have distinctive feature ,which are different from other providing an individual characteristics.

“hence every one is gifted and special “

Similarly in the case of human and chimpanzee (“our closest relative”)

Similarity in the genomic sequence is 99.9%

Genomic variation includes mutation and polymorphism.

“Mutation ”-the mistakes which occurs occasionally during the copying of the genomic sequence .which passes from one generation of organism to another during the reproduction.

When a mutation occurs in a sex cell—a sperm or an egg—it can be passed along to the next generation of people. Your genome contains about 100 "new" mutations

“not every mutation is bad ”,but yes this is what makes you different from other.

“polymorphism”-the simultaneous occurring of in the population of alleles showing variation at given position

Polymorphism can occur in the single nucleotide base causing the formation of the SNP(single nucleotide polymorphism) .

The human genome contains more than 2 million SNPs.

Sites of variations Variations are found throughout the

genome ,on everyone of the 46 chromosome . Variation are not distributed evenly . Some parts of genome are the hotspot of

variability ,with 100s of possible variations. Some part of genome remains same , they are

said to be stable . Major variety found outside the genes ,that

does not effect the persons characteristics say they are useless .

Why should we study genome variation?

genome variation consist many practical application.

These application include genome mapping , screening of genetic disease .

Forensic technologies such as DNA fingerprinting .

Phylogeny

Phylogeny is the evolutionary history of a species or group of related species

The discipline classifies organisms and determines their evolutionary relationships

fossil, molecular, and genetic data are used to infer evolutionary relationships

history In the 18th century, Carolus Linnaeus

published a system of taxonomy based upon the similarity of the organism

features of this system were: two-part names for species and hierarchical classification

Taxonomy is the ordered division and naming of organisms

Phylogenetic tree A phylogenetic tree is a branching

diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.

It is based upon the information about morphologies, genes, and biochemistry of living organisms

similar structure or DNA sequences are likely to be more closely related than organisms with different structures or sequences

Use of phylogeny We can find out the evolutionary relation

among organisms ,which are not slightly visible from their physical appearance . For example phylogentic relation of whale .

Study in medical biology was able to be modified by the help of phylogeny .example considering the impact of HIV on the ancestral species coming out to be that it was not ancient .

Synteny

The relationship between chromosomal region of different species where homologous gene occur in same order .

We can say that the gene sequence present in a one chromosome is matching with the gene location of other chromsome .

Sometimes, duplications of chromosomal segments leads to syntenic regions within the genome of the same species

it has been found that closely related species have fairly similar gene order on their chromosomes, leading to large syntenic regions

Example

Comparison in the mouse and human genome sequence shows that more than 90% of the genome lies under the syntenic block .

Containing 342 syntenic segments . Syntenic relationship between mouse

chromosome and human chromosomal set ,21 segments in the mouse chromosome have there syntenic counterparts in the human chromosomal sets .

Grass genome comparison

Genomes of the following crops are represented according to their colour respectively .

Rice have the smallest genome size hence it is place inside the circle .and wheat does have the largest .

Green dots are representing the syntenic region lying in there specific position of the chromosome of each species.