Chromosomes are structures inside the cell nucleus. An adult human has roughly 15 million cells of various kinds, like brain cells, red blood cells, and liver cells and they all contain set of chromosomes. Human set of chromosomes makes 23 pairs — always one from mother and one from father. Inside each chromosome is a tightly wrapped coil of a chemical, deoxyribonucleic acid, commonly called DNA.
DNA is actually made up of millions of even tinier chemicals called bases. These bases are of four different types:. A gene is a short section which includes the four types of basis in a certain sequence.
A chromosome can contain anywhere from hundreds to thousands of genes. These genes provide a template of you. For example, they ultimately determine your height, body build, and eye color. An inherited trait is any gene-determined characteristic and is most often determined by more than one gene [1].
A gene can be turned on and expressed or simply remain dormant. Your internal chemistry and hence these body processes can also be influenced by external or environmental factors. All plant and animal cells contain many thousands of different genes and typically have two copies of every gene. The two copies, alleles , may or may not be identical and one may be dominant in determining the characteristic while the other is recessive. For example, brown eye color is dominant while blue is recessive.
So, if a child is born with one gene of each color passed on, that child will be brown-eyed. A parent does not have to have the gene expressed in order to pass it on. It is entirely possible that two blue-eyed parents will produce a brown-eyed child. It is also possible that successive children may have blue or green eyes. To do this we look at how many loci have different alleles loci is the plural of locus or site.
Locus is like a physical address for a gene on a chromosome [2]. Genetic diversity of a species is high when there are many different allelic forms of all genes and when there are many different combinations expressed across the species. Sometimes populations are examined for their heterozygosity, that is the percentage of individuals in a population that have differing alleles at a particular locus.
The bases of DNA discussed above: adenine, cytosine, thymine and guanine along with their chromosomal backbone are known as nucleotides. Genetic diversity can also be measured by examining nucleotide diversity.
Nucleotide diversity is the percentage of positions within the genome where two individuals of a given species have different DNA bases. Apart from counting genes, scientists sometimes use deductive logic in determining levels of genetic diversity. An example is the cheetah, a wild cat capable of running 70 miles per hour. Cheetah is a vulnerable species suffering from a number of pressures:.
Due to these numerous problems, cheetahs have very few mating options. Looking at their genetic diversity, it is estimated that present-day cheetah population genomes have less than 10 percent heterozygosity percentage of individuals in a population that have differing alleles at a particular locus. In the case of cheetahs, apart from counting genes, scientists presume that many are closely related by looking to the high success rate of skin grafting.
If a skin graft from another cheetah is readily accepted, it means that both animals are genetically similar. Their immune system recognizes the graft as if it originated from the same individual.
Another sign of being related is asymmetrical skull development. A survey of museum specimens has confirmed asymmetrical skulls prevalent among cheetahs [3]. Still, all may not be lost as life is indeed resilient. Cheetahs survived a similar contraction bottleneck of their numbers between 6, and 20, years ago and it may be that their genetic diversity is still slowly rebounding [4].
Biodiversity is the variety of life in the world. Conversely, a population cannot evolve to adapt to environmental change without genetic diversity [5]. In our world of diminishing biodiversity and dramatic environmental changes, the maintenance of high genetic diversity has become a conservation priority [6]. Genetic diversity is created when different members of a species breed and pass on copies of their respective genes.
The more variety of physical traits between the parents, the greater the possibility of diverse genetic characteristics being passed on to their offspring during fertilization. The number of different genes available affect genetic diversity. A large gene pool with a variety of different genes allows for more differences.
Consider the mating of a dark-skinned, brown-eyed stocky native human from the tropics in Ecuador with a lithe fair-skinned, blue eyed native of Sweden. Should their offspring then mate with the offspring of a red-haired Irishman and an Aleutian or perhaps an Asian.
What is the Law of Tolerance? Can you explain how evolution and biodiversity are related? What are some examples of an ecological niche? What is an example of an animal and their niche for the grassland savannah biome? What are the niches of algae, duckweed, salvinia, and elodea? What is a quick explanation of the difference between a fundamental and realized niche?
How is natural selection related to the concept of niche? What is an example of an ecological niche? What is the difference between a broad vs. Do humans have a niche? What is it? Is it possible for two organisms to live in the same habitat but have different niches?
What is the difference between species diversity and species richness? Whats the difference between species richness and species evenness? Will you explain the relationship between habitat size and species diversity? How do species richness and relative abundance of species affect species diversity? What are factors that may affect diversity levels in a given community? What are the human impacts on species diversity? Which biome most likely has the greatest diversity of living organisms?
What are some examples of loss of species? How is species diversity measured? What is species diversity? How does species diversity change as succession occurs? How can latitude affect species diversity?
How can species diversity affect ecosystem stability? How can species diversity be maintained? How does diversity affect species survival?
Mandira P. Sep 13, More diversity means better chances of survival. Explanation: Increased genetic diversity leads to increased chance of species survival. David Drayer. Aug 21, Explanation: The Cheetah population of Eastern African is in great danger of extinction because the Cheetah are so superbly adapted to their environment that there is little diversity.
Related questions What is the Law of Tolerance? Can you explain how evolution and biodiversity are related? What are some examples of an ecological niche? What is an example of an animal and their niche for the grassland savannah biome? What are the niches of algae, duckweed, salvinia, and elodea? What is a quick explanation of the difference between a fundamental and realized niche? How is natural selection related to the concept of niche?
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