Sample Methodologies for DNA Extraction and PCR for gender identification of Gallus gallus domesticus
DNA extraction and PCR have been used in numerous research projects, current research commonly utilise such techniques for the basis of their study and as economic cost of the proceduredecreases it will become even more prevalent in industrial and commercial settings. A variety of methods collection can be employed in order to extract DNA; the methods chosen can however directly affect the results obtained. Destructive methods such as muscle DNA extraction usually present samples of high quality but would require harming the organism for extraction, similarly blood DNA extraction would be of comparablequality but would be less detrimental than a muscle biopsy. The indirect method (feather) would be difficult to extract DNA as the quality of DNA would be poor however it wouldn’t require harming the species. The difference in quality of the expected DNA extraction would in turn reflect the amount of DNA concentration available; higher quality DNA specimens generallyhave a higher concentration of DNA. Differences between the availability of specimens can also differ between these methods; feathers are highly available for analysis while blood and muscle would be scarce in comparison. Blood and muscle specimens would require cold storage in order to prevent DNA degradation, unlike feather samples which would most likely be degraded. The identification of gender in birds has always been problematic; few species have distinct visual cues (sexual dimorphism) in accordance to their gender. Sexually monomorphic species are present in the wild and are difficult to identify,in addition to this bird progeny are often monomorphic in their development, and hence early determination of gender would be similarly difficult.In regards to Gallus gallus domesticus, the common chicken this difficulty in gender identification is quite evident in their progeny.After fertilisation, sex determination is based upon the inheritance of sex chromosomes; later in embryonic development sexual phenotyping occurs, which is regulated by genetic and hormonal pathways. Sex determination can also be decided by either environmental or genetic factors (Chue et al, 2011). It is integral to realise that sex-linked phenotype traits or allozyme markers are not always determined by sex-linked genes, due to the fact that some sex linkage can be an outcome of specific sex gene expression of autosomal genes (Shikano et al, 2011). Heterogametic sex refers to two different sex gametes attributing to the gender of a species; heterogametic sex can be used as a genetic marker for gender identification in monomorphic species. Identify the sex chromosomes would allow for the gender of the species to be determined accurately. In regards to the avian species inclusive of a few fish, reptiles and crustaceans, the ZW determination system separates genders. The area of interest for this experiment is the CHD1 gene, where CHD1 gene is present on both the W and Z chromosome (Ito et al, 2003). In the context of the experiment, the use of DNA extraction and PCR could provide a relatively simple and accurate determination of Gallus gallus genders through various methods of DNA collection. This experiment will to analyse the viability of DNA extraction from various samples in the use of gender identification of known samples of Gallus gallus domesticus. AIM:
Analyse and compare experimentally determined genders from PCR reactions of known samples of Gallus gallus through various specimen types. METHOD:
Initially a variety tissue samples were collected from a specimen of Gallus gallus domesticus. The tissue samples were of three different types; muscle, blood and feather. The different samples required unique methods of DNA extraction and purification. Muscle tissue samples were isolated from a scalpel-maceration section; the samples were then later transferred into...
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