Multiple alleles and sex chromosomes Assignment

Multiple alleles and sex chromosomes - Assignment Example A person’s blood type is determined genetically. It is imperative that a thorough understanding of the DNA is ascertained for better grasping of the multiple alleles’ direct contribution to the inheritance of ABO blood systems. Histones allow the packaging of DNA and condense it into chromatin. Histones are highly alkaline proteins with a positive charge while DNA is negatively charged (Pollard and Earnshow, 2007). Accordingly, Histones and DNA will interact with the Histones acting as spool materials in which the DNA can attach itself. Histones and the DNA will form the nucleosomes, which on further packaging and separation by linker DNA’s, result in chromatins. Further condensation of the chromatins and other proteins will result in the chromosomes. Chromosomes can, therefore, be defined as a carrier of genetic information as it contains highly packed DNA and Histones (Pollard and Earnshow, 2007). DNA consists of nucleotide substances that are further comprised of deoxyribose, phosphate groups and the four bases. DNA is generally a linear sequence of ACTG bases that define the physical traits in an organism. DNA can be viewed as a double helix, which when separated produces two parallel linear strands of the nucleotide letters where each strand is complimentary to each other (Pollard and Earnshow, 2007). A interlocks with T while G interlocks with C. The exact order of the four bases along the molecule represents the coded genetic information. ... Genomes are the genetic information defining each organism, which is determined by the genome sequences depending on how the four bases are aligned (Pollard and Earnshow, 2007). It is also important to note that apart from genes, a genome also contains other DNA sequences that do not encode genes. The human body has three billion pair of DNA, 28000-34000 pairs of genes and 23 pairs of chromosomes (Pollard and Earnshow, 2007). This translates into a myriad sequences which could explain the wide scope of genes. Genes are the basic and structural and functional units of genetics; therefore the basic unit of inheritance that is composed of DNA and RNA. They control the cells by directing the formation of proteins. An allele is an alternative form of a gene and it represents the different version of a similar gene (Pollard and Earnshow, 2007). A gene is comprised of two alleles and each individual carries only two alleles of each gene, which exhibit a dominant recessive relationship. The dominant allele will prevail over the recessive gene and is responsible for the resulting phenotype. Recessive alleles will, therefore, not affect the phenotype of the individual. A pair of allele resulting from the various combinations of alleles can be referred to as the genotype while the resulting physical trait as a result of the genotype is called the phenotype (Pollard and Earnshow, 2007). Multiple alleles arise where there are three or more different alleles of a particular gene in a gene pool. This results into polymorphism where two or more phenotypes exist in a given population (Pollard and Earnshow, 2007). The occurrence of multiple alleles can be attributed to difference in the non-coding DNA found between genes rather than