How The Environment Affect Sex Determination

Male or female gender is determined primarily by sex chromosomes caused by genetic chromosomes. Recently, it can be said that the environment part contributes to sex determination. Though they are so many environmental factors that can influence the timing of such production, such as humidity, cell type, temperature, food, birth place, and sexual intercourse, Focus on other factors. Most reptiles show a temperature dependence determination that produces women ranging in temperature from 20 to 27 degrees Celsius and men in the temperature range above 30 degrees Celsius. The temperature is in the middle.

The sex of most snakes and most lizards is determined by sex chromosomes during fertilization, but the gender of most turtles and all crocodiles is determined by the environment after fertilization. In these reptiles, the temperature of a particular growing ovum is a factor determining sex, and slight changes in temperature can cause a significant change in sex ratio (Bull 1980). Typically, eggs incubated at low temperature (22 - 27 ° C) produce one sex, but eggs incubated at higher temperatures (above 30 ° C) produce another sex. It is only a small temperature range that men and women can hatch from the same group of eggs. Figure 17.20 shows the change in sex ratio of the red ear slider to the sudden temperature. If the egg hatches below 28 ° C, all the turtles hatching from them will be males. Above 31 ° C, one egg will produce a female. There is also a change in this theme

Body temperature dependence determination (TSD) is an environmental sex determination in which the temperature experienced during embryo / larval development determines the sex of the offspring. It is observed only in reptiles and teleost fishes. TSD is different from the common chromosome sex determination system of vertebrates. It is the most common and studied type of environmental characterization (ESD). Several other conditions, such as density, pH, background color of the environment, have also been observed to change the sex ratio, and depending on the mechanism involved, it can be categorized as temperature dependence determination or temperature dependent differentiation I can do it.