Pt1420 Unit 1 Assignment

Horizontal gene transfer occurs when genes are exchanged between species on different evolutionary routes instead of vertically from parent to offspring. This can be expressed from a tangled web of life over a cladogram. When comparing my cladogram from table 3-1 to figure 3-1, many differences and similarities can be seen. In contrast, my cladogram is a completely straight and increasing line with three different domains of life as terminal taxon and separated with various characteristics. It also shows how some domains, like bacteria, has autopomorphic traits while other traits can be synapomorphic between the three groups. My cladogram also shows Domain Bacteria as the outgroup whereas Domain Archaea and Eukarya are the in-group being studied. It includes nodes and terminal branches and shows which domains evolved more recently than the other or how closely they are related to each other. However, in the web of life, it does not specify what characteristics separated each domain. Instead, each branch ends with a different kingdom that can be classified into the three domains and its branches crisscrosses to express horizontal gene transfer.

Many biologists segregate prokaryotes into kingdom Bacteria and Archaea. There are three domains, Archaea, Bacteria, and Eukarya. Biologists have inferred that the three domains are the three divisions of life. Some biologists continue to evaluate the origin and relationships of the domains. They have found that evolution is not always linear. Among the course of evolution, genes are passed down ‘vertically’ and swapped laterally from one generation to another. Horizontal gene transfer or lateral gene transfer is when genes exchange amongst organisms in one taxon and related organisms in another taxon. This process is common and can appear in several ways like the exchange of DNA between different

Aphids possess bacteriocytes that are specific to its obligate mutualist, Buchnera aphidicola. It seems that this genus has lost genes that are essential to its life. Through Southern Blot analysis, Nikoh and Nakabachi have shown that these lost genes are actually encoded in the aphid genome. Through detailed structural and phylogenetic analyses, the full-length sequences of these transcripts were determined. This demonstrated that these transcripts are indeed significantly similar to multiple bacterial genes. While the Buchnera no longer possess these genes, other similar bacteria (E. Coli) possess these genes. Nikoh and Nakabachi were able to conclude that they found several pieces of evidence that show that aphids are indeed able to acquire genes from bacteria through lateral gene transfer. They also claim that these genes are used to maintain their obligate mutualistic relationship with the bacteria,

The phylogenetic tree is also known as the evolutionary tree. As the name suggests, it represents the relationship of evolution in different animal species of animal that are represented in a tree-like diagram or branching diagram. The taxa that are drawn into diagram are according to their differences and similarities in their genetic and physical materials. The animal that is seen today is at the tip of the tree is the modern animal. The tree is often branched out from a common ancestor into various species because of gene mutation or environmental factor. Animals with common descendants have similar trait among them, and this is referred as homology that can be in the structure like gene sequence.

Many geneticists believe that all current life stems from one common ancestor in a tree of life fashion. Over millions of years, this process of speciation has created numerous kinds of creatures, many of which we are still discovering today. For instance, a rare phenomenon, occuring only in particular environments, was dubbed as a “ring species” by scientists Ernst Mayr and Theodosius Dobzhansky and may help to create this great biodiversity (Pereira & Wake, 2015). When a species becomes separated and can no longer interbreed, the gene flow between these two populations discontinue, which leads to the development of two entirely different species (Martins & de Aguiar, 2017). Researchers have documented this extraordinary event,

It is a fact that 80 % of the earth’s history is solely a microbial life and continues to be a dominant life form. Living organisms can be grouped into three different domains: Archaea, Bacteria, and Eukarya. The differences between these three domains is concerned with rRNA, cell membrane lipid structure, and the sensibility to antibiotics. Prokaryotes includes members of bacteria and archaea while eukaryotes contain organisms that belong to the eukarya domain. For this compare and contrast we will only focus on two domains which are archaea and bacteria domains.

(1a)The history of any species is a fascinating thing that is constantly changing. Mutation and sex are two mechanisms that take a huge part in creating history. Sex combines two different strands of DNA to create a new sequence of amino acids. While mutation changes the sequence of DNA by substitution, insertion, deletion, and frameshifting. (1b)Every species has some relation to another species since we all came from a common ancestor. A way we represent this is with phylogenetic trees. In the example below organisms are arranged based on the differences in their cytochrome c amino acid sequences.

The sequence of the chemical bases in DNA both specifies the order of amino acids in proteins and determines which proteins are synthesized in which cells. In this way, DNA is the ultimate source of both change and continuity in evolution. The modification of DNA through occasional changes or rearrangements in the base sequences underlies the emergence of new traits, and thus of new species, in evolution. At the same time, all organisms use the same molecular codes to translate DNA base sequences into protein amino acid sequences. This uniformity in the genetic code is powerful evidence for the interrelatedness of living things, suggesting that all organisms presently alive share a common ancestor that can be traced back to the origins of life on

A protein enzyme within the acidocalcisome is traced back in history that is common all throughout the bacteria, archaea and eukaryotes. This protein was then used to distinctively make a so-called family tree to trace back through time through all three of these domains. This tree has shown the various different genes that were commonly related to each three domains as well as being compared to the tree constructed for the universal common ancestor. With the few distinct evidence provided, the LUCA was hypothesized to be a more complex than the most

2. Similar genetic sequence can indicate close relationships between different species because DNA accumulates mutations over time like a molecular clock. Organisms are closely related. If these sequences aren’t conserved for a functional purpose, then they will suggest descent

Co-speciation is the shared speciation of two or more lineages that are ecologically connected, the paradigm example being a host and its parasite. The association need not be parasitic; symbiotic, mutualistic, and other relationships may also demonstrate co-speciation. Co-speciation is the process whereby one population speciates in reaction another, and is a consequence of the associates dependence on its host for its survival. If this occurs for all instances of speciation by the host, the associate and host phylogenies would be topologically identical. This notion was formalised by Fahrenholz in 1913, however, in almost all instances of cospeciation, except those cases where the host is pathologically dependent on its associate, this principle is rarely strictly adhered to. Exceptions to a strict interpretation of Fahrenholz ‘s rule are revealed by topological incongruence between the host and associates phylogenies. Consequently Farenholtz’s rule is an important methodological tool for reconstructing the history of cospeciation between hosts and their associates. Nevertheless, it should

Humankind needed a guideline in order to comprehend the nature of organisms. For that reason, scientists began to arrange organisms formally into groups called taxa. Ernst Mayr defined taxon as a single taxonomic group of any level that is unique and independent from other groups. (Mayr, 1981) Since then, several diverse hypotheses were suggested and majority of scientists agreed to classify organisms into two major domains, eukaryotes and prokaryotes. At that time, the principle of two domains seemed to be fairly reasonable and was widely accepted amongst scientists. Since then, the same definitions for those two

Development in the phylogenetics field in the second half of the 20th century included the introduction of molecular phylogeny and evolution. These additions strongly enhanced the concept of homology. In addition, it was found that homologous structures can develop from non-homologous development precursors. This caused the embryological criterion to fail, and so new outlines needed to be established in order

Bacteria’s ability to horizontally transfer DNA (Deoxyribonucleic Acid) throughout different species is a key factor in the evolutionary success of these organisms and their survival in extreme environments (Averhoff & Muller, 2010). Horizontal gene transfer allows the organism to gain beneficial genetic sequences which allow for a superior evolutionary capability (Averhoff & Muller, 2010). With the capacity to acquire new traits during a lifespan, microbes are potentially the only organisms able to withstand the extreme environmental conditions that exist in space.

As for organisms in the world from humans to the smallest microbe, they directly reflect upon biodiversity, in respect to the appearance, size and expression. The reason behind this is caused by the genetic material found in each and every cell that composes each organism. Given that there are two types of cell organizations found in life, comparison of both ‘eukaryote’ and ‘prokaryote’ genomes will provide a better understanding for such diversity. ‘karyote’ refers to the nucleus, and also ‘pro’ means ‘absence’ and ‘eu’ means ‘presence’. Therefore the words prokaryote and eukaryote reflect upon the individual cell organization. In contrast, the both organizations