Question

Describe how changes in the environment can alter expression?

Answer 1

Answer-

According to the given question-

• We know that in an organism the gene expression can be influenced due to the environmental condition. The gene expression depend upon the external factors present in the environment such as the location of organism, their development as well as internal factors found inside the organism such as metabolism and the hormones. But the most internal environmental factor that influence the gene expression is the gender of the organism, observed in case of sex-limited as well as sex-influenced traits.
• The external factors include chemicals, temperature, drugs, chemicals, and light responsible for determining the control of genes, i.e. when they become turned on and when they become off, these factors influence the function as well as development of an organism.
• Sex-influenced traits are defined as the traits that are expressed differently between the two sexes, and are called an autosomal trait, that means, the genes responsible for expression are not found on the sex chromosomes. e.g. male baldness.
• The allele responsible for baldness, that leads to hair loss, is depend upon the high level of dihydrotestosterone as well as testosterone hormones. Generally the males have high level of both the hormones compared to the females, due to which the allele for baldness show strong affect on males compared to the females.
• The Sex-limited traits are also autosomal as well as sex linked , and their expression is observed in only one sex. e.g. production of milk production.
• Chemicals as well as drugs also have strong influence on the gene expression in organism. E.g. Cyclops fish , due to presence of magnesium chloride, they produces one-eyed embryos (Normal is with two eye)
• chemicals such as thalidomide , nonbarbiturate drug work as a sedative as well as antiemetic, influence the gene expression and also have harmful effect on developing embryo or fetuses i.e. leads to neuropathy, stunted limb development.
• Light as well as temperature influence the gene expression in several organisms. E.g. Himalayan rabbits which have the C gene, needed for development of pigments for their skin , fur and eyes is dependent upon the temperature , because the C gene becomes inactive when the temperature exceeds 35°C, and have maximum activity between the 15°C to 25°C.
• So in warm conditrion, as in the central parts of body of the is without pigment and due to which the fur color become white , while in the region of , nose tip , and feet), , generally the temperature is less than 35°C, and the C gene capable of producing pigment, and gives black color.