This state is characteristic for recessive traits. For an individual to express a recessive trait, it must have two recessive alleles (one of two or more alternative forms of a gene) of the responsible gene. But, if it has one recessive allele and one dominant allele, it will not have the trait, but he will be called a carrier. So, it seems like the trait "disappeared" but still it is "carried" in the genome. However, if its offspring has two recessive alleles and express the trait, it will <span>seem </span>like the trait "reappeared".
Variations in species help them to adapt themselves to that particular environment and give them a chance of survival. For example, thermophilic bacteria are variants that are resistant to extreme temperature. They have a chance of survival in high temperate zones while others die.
Specialized cells are stem cells that turn into cells with specific functions
<span>There are so many societal issue that scientists will be able to address using the sequence of the human genome. For example, health epidemics. Using the genome, scientists can easily found how a pathogen affects a population and search for genes that can inhibit the pathogen. But no all health epidemics are caused by a pathogen. The obesity, nowadays a social health issue in so many countries, is an epidemic that can be address using the human genome. Also, the drug Abuse and Addiction. Scientific have found genes that are related to obesity and also genes related to drug addition. A person who have these genes is more likely to suffer those conditions. But, the discover of these genes and the disease relation help scientists to search for a better treatment.</span>
