COI sequence variation
High A+T content and positional biases, e.g., slight bias against cytosine (17.3%) in the first position, in favour of thymine (45.7%) in the second position and substantial bias against guanine (2.9%) in the third position of mitochondrial COI gene fragment was found in all Acetes indicus, A. serrulatus, A. japonicus, A. sibogae individuals analysed in this study (Table 3). This pattern of base composition is similar to the COI gene region sequences in other groups of crustaceans, including Raymunidae (Macpherson and Machordom, 2001), Portunidae (Chu et al., 1999; Pfeiler et al., 2005), Bresiliidae (Shank et al., 1999), Gammaridae (Meyran et al., 1997), as well as some Penaeid shrimp species (Baldwin et al., 1998; Maggioni et al., 2001; Quan et al., 2004; Tong et al., 2000; Zitari-Chatti et al., 2009).
With respect to the amino acid substitutions, COI is considered to be one of the most conservative genes in the mitochondrial genome (Black et al., 1997) and thus only three amino acids substitution was detected in this study. The translation of the 552 bp of COI gene fragment resulted in a sequence of 184 amino acids without in-frame stop codons or indels. Together with the patterns of base composition and base substitutions as discussed above, these observations showed that the COI gene fragment amplified in this study was not a nuclear mitochondrial pseudogenes (Numts) (Bensasson et al., 2001; Song et al., 2008; Zhang and Hewitt, 1996) that have been reported in crustaceans, including in the snapping shrimp, Alpheus (Williams et al., 2002; Williams and Knowlton, 2001).
4.2 Interspecific variation of Acetes sp. and cryptic diversity
From the phylogenetic trees inferred from the COI sequence (Figure 2 – 3...
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T. californicus is found from Alaska to Baja in small, shallow tidepools and tidal flats in the upper spray zone where they cannot avoid the full effect of visible and ultraviolet (UV) radiation. Individuals assemble in areas of lower radiation at midday, yet have no preference to the intensity of light at dawn and dusk (Hartline and Macmillan 1995). These tiny arthropods inhabit all types of marine sediments from sand to fine mud and ooze. Along with plankton, T. californicus eats microscopic algae, protists, bacteria, diatoms, algae and microbes (McGroarty 1958). When the concentrations of the species in their habitats are high, T. californicus will turn to cannibalism for a food source. The nautilus eye present in the species is rich with fatty acids and provides a good food source for the animal.
Paabo’s team discovered an mtDNA sequence from a finger bone they found from around 40,000 years ago, as carbon dating is one of the most commonly used methods of determining a fossil’s age. (Hammer, 70). Also, Neanderthal mtDNA is differs severely from modern human mtDNA. For example, Microcephalin is a gene for brain size during the development of the organism.
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From a crab to a barnacle, crustaceans are a diverse group of animals that inhabit much of the world. This lesson will explore what it means to be a crustacean and will also provide some example organisms.
contains mitochondrial DNA (mtDNA), completely intact. Mitochondrial DNA is tougher than the DNA found in cell nuclei; it is also found in the cytoplasm of a fertilized egg and is passed only through maternal lineage. This makes it much easier for the team to study and makes testing more accurate. Paabo’s team, from Leipzig, Germany, used a method of amino acid content as a way of measuring extractible DNA from the bones. The amino acid method was a means for testing the DNA content in the fossils.... ...
Mitochondrial DNA is relatively short, only 16 569 bp long, and codes for just 37 genes. It has been completely sequenced (the order of the bases has been worked out) and is very well studied and understood by molecular biologists. There are about 800 m...
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Taking the theory of paternal mtDNA leakage during embryogenesis into account, the process of embryogenesis needs to be studied. Embryogenesis is the formation and development of embryos where after the egg is fertilized by the sperm, the sperm mitochondria enter the egg cell. Here in the egg is where the sperm mitochondria are outnumbered by the maternal mitochondria and are killed through a mechanism that identify the ubiquitin sperm are tagged with. Thus paternal mitochondria do not transmit to further cell stages of embryo development and mtDNA is solely believed to be maternal in inheritance. Taking the case study into account, the question that is raised is how paternal inheritance of mtDNA could have occurred if embryogenesis prevents it. Therefore, the further research in recombination of mtDNA can be conducted to see if mtDNA can be similar to nuclear DNA, where mtDNA can be incorporated or fused from many sources (Bromham et al 2002).