**4. Genome-wide association studies (GWAS)**

Genome-wide association studies (GWAS) are a new technique used worldwide in genetics research to identify inherited genetic risk variants linked with risk of prevalent disease. GWAS are the most inclusive way of genetic variation study. In general, this approach deals with full scan of genome for identifying genetic markers frequently are polymorphisms (SNPs) that appear more in patients relative to healthy individuals, and also understanding the contribution of genes in the diseases and developing better prevention and treatment approaches.

GWAS are the greatest complete way of research and contain skimming the whole genome of research members for polymorphisms and anomalies related with the sickness of attention. GWAS have the benefit of supplying a complete investigation of related genetical anomalies inside the genome, as the term "genome-wide"

**9**

**5. Discussion**

**Figure 6.**

*Genome-wide association studies [71].*

*Genetic Polymorphisms*

*DOI: http://dx.doi.org/10.5772/intechopen.88063*

shows, in spite of that, GWAS are timing spender, costly, and yields a massive quantity of data that can/cannot actually be related to the illness of study. As of that, they are best beneficial as an initial mark pretty than a way for measuring accurate connotation [67]. In additional, GWAS are case-control study setup concentrating on obviously distinct participators geneticists who assume to find only proportionally brief extends of participate chromosomes **Figure 6** [67]. It includes comparison between two groups of individuals, one healthy and second patients or affected group with disease. Therefore, GWAS purpose is to recognize hereditary variations that convert danger of public maladies or touch additional phenotypes. The simple thought of it is: check hereditary variations (frequently SNPs), and phenotypes in haphazardly-tested persons, and view which SNPs are connected with phenotypes,

while infrequent variations are inferiorly taken by GWAS method [68–70].

All humans have variation in genetic material, even identical twins by the time of born, and this variation give us the uniqueness. We inherit our genes from our parents, so the members of the same family share majority of their genetic material involving its variations. The variation in DNA that cause wrong in required genetic code translates into a specific protein called pathogenic variant or mutation when linked to phenotypic particularly if they occur within the protein coding sequence of the gene. Variations are caused by the environment and genetic factors. Several disorders arise from multiple effectors like environmental, lifestyle, and

*The Recent Topics in Genetic Polymorphisms*

*3.2.1 Variable number of tandem repeats (VNTRs)*

100 units [63–65].

tandem repeats (STRs) [66].

*3.2.2 Short tandem repeats (STRs)*

**3.3 Insertion/deletion polymorphisms**

frequent insertion/deletion as indels [55].

**4. Genome-wide association studies (GWAS)**

depend on the distance of the repeated blocks. In microsatellites, the order repeat base composes between 2 and 9 units; while mini-satellites composes between 9 and

VNTR is among the earliest DND markers in the application. It is a kind of tandem repetitions in which a small order of bases (10–60 base pairs) are frequented changeable times in a certain position. Therefore, VNTR is additionally familiar as minisatellites. Minisatellites are scattered everywhere in the humane DNA. Usually, the number of repeated bases in minisatellites differs among persons. Hence, the array extension shaped by VNTRs as well differs among persons. Accordingly, the variant number of chromosomes is familial from parents, so they can be applied in parental or individual identification. The techniques that use to determine this type are: routines PCR, gel electrophoresis, and amplicons of band designs by southern blotting. The utilization of VNTRs was, nevertheless, restricted by the kind of specimen that could give good results for the reason that a big quantity of DNA was needed. In addition, understanding VNTR profiles might be a difficulty. Their utilization in forensic genomics has been replaced at the present time by short

Short tandem repeats (STRs) give an extremely good method because of their great grade of polymorphism and a comparatively small length. Additionally, STRs are typical methods for genotyping in the identity of one's parents check and forensic identity check. A category of tandem repeats depended on presents a small order of bases (2–6 base pairs) are frequented a variable number of times in a certain site. STRs are a type of microsatellites, and they are furthermore recognized as short sequence repeats (SSRs) in plant DNA. The repeating bases consist of a single

It is a type of genomic difference in which a particular base order of different sizes ranging from one base to several 100 units is inserted or deleted. Indels are very extending across the DNA. Several writers consider one base pair as SNPs or

Genome-wide association studies (GWAS) are a new technique used worldwide in genetics research to identify inherited genetic risk variants linked with risk of prevalent disease. GWAS are the most inclusive way of genetic variation study. In general, this approach deals with full scan of genome for identifying genetic markers frequently are polymorphisms (SNPs) that appear more in patients relative to healthy individuals, and also understanding the contribution of genes in the

GWAS are the greatest complete way of research and contain skimming the whole genome of research members for polymorphisms and anomalies related with the sickness of attention. GWAS have the benefit of supplying a complete investigation of related genetical anomalies inside the genome, as the term "genome-wide"

diseases and developing better prevention and treatment approaches.

nucleotide that is familiar as a single nucleotide polymorphism (SNP) [66].

**8**

#### **Figure 6.** *Genome-wide association studies [71].*

shows, in spite of that, GWAS are timing spender, costly, and yields a massive quantity of data that can/cannot actually be related to the illness of study. As of that, they are best beneficial as an initial mark pretty than a way for measuring accurate connotation [67]. In additional, GWAS are case-control study setup concentrating on obviously distinct participators geneticists who assume to find only proportionally brief extends of participate chromosomes **Figure 6** [67]. It includes comparison between two groups of individuals, one healthy and second patients or affected group with disease. Therefore, GWAS purpose is to recognize hereditary variations that convert danger of public maladies or touch additional phenotypes. The simple thought of it is: check hereditary variations (frequently SNPs), and phenotypes in haphazardly-tested persons, and view which SNPs are connected with phenotypes, while infrequent variations are inferiorly taken by GWAS method [68–70].
