Scientific curiosity has been a very strong reason behind hybridization (Purdom, 1993). However the need to take full control of production outcomes as well as to increase productivity seems to be a greater force behind the initiation and use of hybridization. Hybridization of Tilapia for monosex production has been reported as far back as 54 years ago (Whitehead, 1960). The ease of interbreeding between various Tilapia strains and stocks naturally has been a source of concern to aquaculturists and conservationists alike (Pullin, 1993, Steffens and Hilge 1999, Allendorf et al., 2001, Perry et al., 2002, El-Sayed, 2006). However, natural selection as a process limits the extent of hybridization between closely related species but the major concern is the further hybridization and back crossing of F1 hybrids from the successful hybridizations in nature hence introgression with associated deleterious effects (Penman, 2005) which includes loss of skin hue, reduction in viability and production of fertile offspring (Bartley et al., 2000) that can still reproduce more. Earlier report by Kocher (1997) revealed heterozygosities of less than 10% in farmed tilapia strains as against the wild strains. Therefore, intensive hatchery management becomes necessary to avoid escapes and hybridization of F1 offspring as well as back crossing with female parents (Chevassus-au-Louis 2002).
The starting population in the experiment contained 100 organisms of Dottus Variengatus. The results of both parts of the experiment rejected the null hypothesis tested. The Dottus variegatus individuals experienced negative selection effects by predators based on their bright and distinctive phenotypes that made them stand out among the rest of the population. Individuals with lighter colors represented the adapted individuals which experienced positive selection pressure. These individuals were benefited by predation because they survived and could continue to pass their alleles and contribute to the gene pool of the future population.
It was used because of its rapid rate of reproduction, The objective of this lab was to determine whether the two crosses conducted fit the expected results of a 9:3:3:1 ratio, which could be done using the Chi Squared Test. The 9:3:3:1 ratio meant that the phenotypes of the F2 offspring would occur in a nine: three: three: one ratio- 9 would be wild-type or normal, 6 of the offspring would have one normal and one mutant characteristic and lastly one of the offspring would be a mutant for both phenotypes. Two distinct crosses were conducted during this experiment: one using red eyed, ebony bodied males and white eyed, brown bodied females as the F1 generation and the other cross using white eyed, brown bodied males and red eyed, ebony bodied females. Our hypothesis, or prediction was that crossing offspring from the F1 generation, or the F2 progeny would fit the expected outcome of a 9:3:3:1 ratio as
With further research I learned of gamatic isolation and preyzgotic barriers, which is the reason as to why simply put, differing species are just not able to create hybrid organisms of the two. The first barrier to hybrid and chimera creation is preyzgotic barriers, which limit the chances of different species from even coming into contact with one another. Prezygotic barriers can include factors such as differing mating rituals, and differing environments. However, if two species successfully manage to make contact with one another, gamatic isolation is the reason as to why the said egg and sperm cannot successfully combine, therefore making crossbreeding with certain species is simply
If the genetic aspects of the two populations show significant differences, then it is reasonable to make inference about their divergence. Johnson and Marten (1988) illustrated the differentiation of allopatric populations by examining 41 genetic loci in 11 breeding populations through electrophoresis. By examining the allelic frequency in coastal and interior populations, some alleles appearing in one population with high frequencies do not exist or have low
Period 5 Quarter 1 Final Essay by Anish Kashyap Harrison Bergeron by Kurt Vonnegut Jr., The Monsters are due on Maple street by Rod Serling, and Pros and Cons of Genetic Engineering in Humans by Matt Bird all show that a utopian society is destined to fail. The ways of life in each society show that utopian societies are destined to fail. In Harrison Bergeron, the society is destined to fail because everyone is the same and they have strict laws. In The Monsters are due on Maple Street, the neighborhood is destined to fail because people are prejudiced against others and people make illogical conclusions.
The results of the gel electrophoresis are summarized in Figure 2. On the gel, both populations of fish were run and analyzed for their heterozygosity. Following the conclusion of the electrophoresis, the gel was analyzed to determine how many different alleles were present at the SFMSTR5 loci. The results of the analysis are shown in Figure 2. The gel showed that in population 1, there are three different alleles at the SFMSTR5 loci and that a majority of the fish in this population are heterozygous at this locus.
Fish have been used in scientific research for a long time, less so than other animals such as rats and mice but at an increasing rate since the 1960s. Fishes are used as experimental models in biological sciences 1 and rainbow trout (Oncorhynchus mykiss) is one of the most intensively studied fishes in a broad variety of research areas. Even though they are large in size relative to some other model fish species, and have fairly long reproductive cycles (2-3 years), they are easy to culture. Trout are more amenable to surgical manipulation than smaller species, and their size allows large amounts of specific tissues and cell types to be isolated for biochemical, immunological, and molecular biological analysis. Rainbow trout reproduction is
Gila trout are endangered in some stretches of water that are managed as designated wilderness. A hands-off policy would be their doom. Because exotic trout species now swim in the same streams, Gila trout can survive the competition and the temptation to interbreed only if they swim in isolated tributaries. In which a water-fall blocks the upstream movement of other fish. Two decades ago, one such tributary was fortified.
For as far back as history can see scientists have been working to uncover and categorize different organisms as they relate to groups we are currently aware of. One of the many conflicts with naming newly discovered groups is that our system for classifying is still developing. There are blurred lines and special exceptions that make scientists question what really determines a group of organisms as it’s own species. When discussing distinct species what most commonly comes up is the factor of reproduction, more accurately reproductive isolation. They are able to interbreed with individuals in their species, but produced infertile offspring when mating with other closely related groups (Cawley, 1).
These fish have become incresingly popular due to the films “Finding Nemo” and “Finding Dory”. Although there is no evidence of population decline thus far, increased demand will cause more fish to be caught, which will decrease populations because there has been no record of successful breeding in captivity (Bradford
Artificial Selection/ Natural Selection When the word artificial comes to my mind fake thoughts run through me, like water runs down your throat. Artificial christmas trees, flowers, foods, anything artificial you can think of, almost everyone has it and has produced it. As you read this, do you have any idea what artificial means? Said on dictionary.com, artificial means produced by humans, not occurring naturally. For example, artificial selection would be taking a wild animal, such as a whale, living in the huge ocean and putting him/her in a place like Seaworld, where they don’t adapt to the environment well, and are not used to the resources and rules.
Polyandry in Anuran Amphibians Polyandry is a breeding pattern where the female mates with multiple males in one mating season, this topic is described by Byrne and Roberts (2012) as a poorly understood topic in evolutionary biology. Polyandry has two types in taxa with external fertilization, e.g. anuran amphibians: simultaneous and sequential polyandry. Simultaneous polyandry occurs when sperm from multiple males compete to fertilize eggs. Sequential polyandry occurs when the eggs from a single female are fertilized by multiple males and sperm competition is absent (Byrne and Roberts 2012).
Background Cloning is the process by which an identical replica of any living organism can be created. Clones are organisms that have identical genes as the original organism. That indicates that each organism 's DNA, when cloned, is identically remade. Since cloning has first been discovered, many animals and crops have been cloned.
Is Genetic engineering Safe? Genetic engineering is the modification of an organism’s genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species. Human beings ought to consider the pros and cons of genetic engineering before using it. It is a contentious topic because people have different views of weather genetic engineering is safe or not.
Introduction The practicum has been developed in RIKEN Centre of Developmental Biology in Kobe, in the laboratory of Axial Pattern Dynamics under the supervision of Inomata-sensei and Matsukawa-san. In the laboratory they try to artificially regulate the gradient shape, they can control morphogen-dependent pattern formation. In general, the shape of a gradient is defined by three factors; synthesis, diffusion, and degradation of morphogen.