Which of the following is NOT an example of an epigenetic phenomenon provided by Dr. Carey on evidence that genetic identity does not lead to identical phenotypes in organisms?

a) kittens turn into cats

b) Maggots turn into flies

c) Some reptiles' genders are determined by the temperature of their nests

d) Humans have 200 different types of cells that develop from 1 DNA code

Answer: c) Some reptile' s genders are determined by the temperature of their nests.

Explanation:

DNA has the instructions for various functional proteins to be produced inside the cell, so it determines the genotype of an organism. The sequence of DNA indicates which proteins will be produced. If there is a change in this sequence, another protein may be produced.

Epigenetics is the study of changes in gene expression that are not caused by changes to the DNA sequence. This means, there is a change in the phenotype (organism's observable characteristics or traits) without a change in genotype. Thereby, epigenetics affects how genes are read by cells, and whether they cells should produce proteins or not, or which specific proteins.

Epigenetic changes can be influenced by many different factors such as age, lifestyle, environment, among others. And ther are three systems known that produce epigenetic changes:

DNA methylation Histone modification Non-coding RNA (ncRNA)

They are associated with gene silencing are considered to initiate and sustain epigenetic change.

In the question, kittens turning into cats is a normal process determined by the DNA, so as maggots turning into flies. Humans having 200 different types of cells that develop from one DNA code is talking about how DNA has the instructions of every process of the body. And according to what genes are transcribed into RNA, those genes will code for specific proteins inside each type of cell, based on the needs of the cellular functions.

But, some reptile's gengers are determined by temperature, it an example of epigenetic. Gender after fertilization because the temperature of the developing eggs is what decides whether the offspring will be male or female. Temperature affects gene activity and expression without changing the DNA sequenced that was established at the time of fertilization.