Question

Discuss how population and/or family pedigree genetic studies use genetic markers to distinguish between DNA variation [Hint: you may wish to include a discussion on Hardy-Weinberg Equilibrium (HWE), finding causative mutations responsible for a Mendelian disease and/or using SNPs in GWAS for complex traits/disorders].

Answer 1

A population or family pedigree tree in order to establish the genetic connection uses different genetic markers and helps in understanding the difference between the DNA variation and how it has helped in diversity. The genetic markers are basically sequences of gene or DNA and its position on the chromosome is known. The genetic markers are used to identify individuals or different as the marker although present in the known location but has variation due to certain mutation or change in the genomic sequence. The genetic markers are specific sequences of DNA and hence are used to identify between different individuals. Such markers are very important for studying the DNA linkage as well as other type of association studies. These markers helps in identifying the position of DNA sequence or gene allel and helps in genetic mapping.

The Hardy Weinberg equation helps in better understanding of population genetics and mathematically it helps in calculating the existence of genetic variation within a population. The equilibrium states that frequency of genotype within a population stay constant from one generation to other when there are no mutations or evolutionary changes. When there are genetic effects like genetic drift, natural selection or mutation, it changes the gene sequence and hence the genetic markers tend to different between species. The mutations can occur due to number of factors like adaptation, evolution etc.

The SNPs are used for the GWAS or genome wide association studies which helps in identifying the genetic variants that exits in a wide genome from different individuals. It helps in studying major genetic diseases that is caused due to change in gene sequence and mostly use the single nucleotide polymorphism as marker. The SNP is when one nucleotide is substituted at one position within the genome and creates a number of variation. The SNP can be used as genetic marker for understanding and learning about variation.