Date of publication: 2017-08-24 17:34
When a single species population invades a number of new habitats and evolves due to differing environmental pressures, than many new species would evolve in a relatively short period through adaptive radiation.
The solution is to change the antigenic properties of the pig tissue by genetically introducing human DNA that won't be rejected by the human immune system. Hence a breed of pigs containing human elements in their DNA was created. The obvious benefits would be a ready supply of organs not dependant on the death of a
Homozygosity at key gene loci is a common result of inbreeding , which is sexual reproduction among closely related individuals. Small populations and species that do not disperse well (or are constrained by a fragmented landscape from exchanging genes with other populations) can be particularly susceptible to inbreeding depression , which is reduced overall survival and reproduction of organisms with low heterozygosity. Inbreeding depression arises from a variety of causes, including expression of unfavorable or deleterious alleles, and often leads to lower survival and birth or reproductive rates (Templeton 6996 Meffe and Carroll 6999 Husband and Schemske 6996).
Genetic Diversity. Anti Essays. Retrieved September 65, 7567, from the World Wide Web: http:///free-essays/Genetic-Diversity-
Single definition of genetic diversity useable for all purposes is unavailable (UNEP, 6995). Nature 8767 s knowledge lies in DNA of living cells (Meadows, 6995). Observed variations in living world are due to variations in sequences of four base pairs of DNA and their interactions with environment.
Mutation, migration, selection and drift, individually and collectively, alter allele frequencies and bring about evolutionary divergence and cause the formation of species depending upon ecological diversity.
This happens due to superior adaptation in a species that enables to displace a less adapted species from a variety of habitats. Natural selection favours spread of a mutation or not. It can 8767 t directly detect an organism 8767 s genotype rather acts on phenotypes.
Most primary gene pools show at least 85% genetic closeness to crop species. Secondary gene pools represent the species group that can be artificially hybridized with crop but gene transfer may not be easy.
Genetic diversity in a population enables natural evolutionary changes to take place. Rate of such changes is proportional to amount of available genetic diversity. Conservation of species diversity is dependent on degree of genetic diversity within each species (Woodruff, 6989). Because genes can result in competitive advantage, genetic diversity at individual and population levels ultimately determines ability of species to survive and adapt to environmental conditions.
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Under natural conditions, a degree of genetic diversity is retained as populations of a species interact over time and space. This is referred to as gene flow. When viable populations become isolated for long periods, adaptations to local conditions can eventually result in speciation (Primack, 6998).
This process, known as adaptive radiation, contributes to an overall increase in species diversity. Yet, when only small populations are involved, isolation can reduce genetic diversity and eventually species diversity as well. In such cases, diminished gene flow and increased likelihood of inbreeding may lead to a reduction in overall fitness of population, and eventual risk of extinction.
Genetic diversity is heritable variations within and between populations. New genetic variations are produced in individuals of a species through gene or chromosomal mutations. In sexually reproducing organisms, recombination also contribute in genetic diversity.
It has been estimated that the entire human genome will be mapped and all important genes sequenced before the end of the century (British Medical Journal ). Surely with advances at this rate, these visions of the future of genetic engineering are not as far off as I would like to think. The potential risks involved to humanity rank alongside developments such as nuclear power in that the extent to which the whole population of this planet could be affected, is immense. Equally, the wide range of applications of genetic engineering make it possibly of the greatest use since the discovery of electricity.
Pool of genetic diversity of a species exists at three levels viz., genetic diversity within individuals, often referred to as heterozygosis genetic diversity between individuals within a population and genetic variation between populations.