The Role of Infections and Diseases in the Evolution of...

Haldane’s hypothesis which states that there is a role of infections or diseases as a driving force in the evolution of Metazoans is simply put as infection is a selective in the evolution of Metazoans and essential for the survival of certain populations. Malaria represents one of the most important selective factors affecting human populations. There are several inherited diseases of red blood cells that lead to resistance at the erythrocytic stage. ÃŽ ±-Spectrin Hereditary Elliptocytosis Hereditary elliptocytosis is a heterogeneous group of red-cell disorders characterized morphologically by oval-shaped erythrocytes (Gallagher, 2005). Ovalocytosis is an uncommon variant of hereditary elliptocytosis (Gallagher, 2005). It is caused by heterozygosity for a 27-base pair deletion in the gene encoding the erythrocyte membrane protein band 3 (SLC4A1∆27) (Williams, 2006) on chromosome 17 (Jarolim et al., 1991). A mutation results in impaired function and gross skeletal disruption of the membrane skeleton of the erythrocyte (Coetzer et al., 1990). It confers highly specific protection against cerebral malaria by maintaining similar parasitemia levels (Coetzer et al., 1990). The heterozygotic form is asymptotic (Coetzer et al., 1990). Ovalocytic erythrocytes are very rigid and relatively resistant to invasion by various strains of malarial parasites (Coetzer et al., 1990). There are four ÃŽ ±-spectrin mutations namely alpha 1/74, alpha 1/46, alpha 1/65 and alpha 1/61 (Coetzer et al.,Show MoreRelatedThe Symbiotic Relationship Between a Bacteriophage and the Mucus Layer of a Metazoan Host576 Words   |  3 PagesThe purpose of the study by Barr et al. is to investigate an assumed symbiotic relationship between a bacteriophage and the mucus layer of a metazoan host, which may create a defense against microbes to protect the mucus layers from bacterial infection. The mucus layer has about four times more phage than bacteria, which is seen in preliminary testing, and because phage encode hypervariable proteins that may aid in adsorption to bacteria prey, the phages may work to protect the mucus layer be adheringRead MoreMitochondrial Pathway Of Mitochondrial And Mitochondrial Permeability Transition977 Words   |  4 Pagesactivated pathways and if the stress cannot be resolved the UPR switch to apoptosis. It is believe that ER-induced apoptosis is mediat ed through activation of caspase 12 in rodents (Figure. 3). The human homologue of caspase-12 is silenced during evolution and it believes that caspase 4 fulfil its function in humans. ER resident BCL-2 family proteins regulate apoptosis through both direct and indirect (ER Ca2+ signaling) signaling pathways (Oakes et al., 2006; Rong and Distelhorst, 2008). For exampleRead MoreRna Interference Regulates Gene Expression9725 Words   |  39 Pageshomeostasis (Bernstein et al. 2001; Tuschl 2001; Zamore 2001; Hammond et al. 2001). It has been estimated that up to 70% of total genes in mammalian cells could be regulated directly or indirectly by RNAi pathways (Bartel et al. 2004; Zamore 2001). The vital role that the RNAi mechanism plays in these processes made itself a subject of tight temporally and spatially regulation (Tuschl et al. 2001; Zamore et al. 2001). Previous studies from our lab and other researchers found that molecular chaperone heat shock