Question

Indicate if the conditions described would result in the development of a male or a female individual. SRY is a gene on the Y chromosome that is involved in initiating the development of the male phenotype in humans.

Answer 1

The presence and functionality of the SRY gene on the Y chromosome dictates the development of a male phenotype, leading to testis formation and testosterone secretion. Without a functional SRY gene, the embryo will develop female sex characteristics by default.

Step-by-step explanation:

The conditions described would result in the development of a male individual if the SRY gene is present and functional. The SRY gene of the Y chromosome in embryonic germ cells produces the testis-determining SRY protein. This sets off a cascade of genetic activations that lead to the differentiation of the bipotential gonadal tissue into testes, which then secrete testosterone to further the development of male sex characteristics. Conversely, if the SRY gene is not present (as is the case for females with XX chromosomes) or it is mutated (as in conditions like Swyer syndrome), the individual will develop female characteristics.

A typical XY genotype with a functional SRY gene will inevitably cause an embryo to develop into a male. However, without the SRY gene or if a mutation occurs within it, the default development of the embryo will be a female. Cellular differentiation within the bipotential gonads will occur towards the formation of oogonia and primordial follicles in the ovary, rather than forming spermatogonia as it would in the presence of SRY.

Answer 2

The question is incomplete. The complete question is:

Indicate if the conditions described would result in the development of a male or a female individual. SRY is a gene on the Y chromosome that is involved in initiating the development of the male phenotype in humans.

a) Only one X chromosome

b) One X chromosome and a Y chromosome with the SRY gene deleted

c) One normal X chromosome and an X chromosome with an SRY gene insertion

d) Two X chromosomes and a Y chromosome

e) An individual with only one X chromosome and a Y chromosome with an SRY gene mutation

f) Four X chromosomes and a Y chromosome

g) One each of the X and Y chromosome

Answer:

a) Only one X chromosome = FEMALE

b) One X chromosome and a Y chromosome with the SRY gene deleted = FEMALE

c) One normal X chromosome and an X chromosome with an SRY gene insertion = MALE

d) Two X chromosomes and a Y chromosome = MALE

e) An individual with only one X chromosome and a Y chromosome with an SRY gene mutation = FEMALE

f) Four X chromosomes and a Y chromosome = MALE

g) One each of the X and Y chromosome = MALE

Step-by-step explanation:

The SRY gene is present on the Y chromosomes of human males and serves as one of the major determinants of sex in humans. The SRY gene regulates the development of testes in the fetus. The release of testosterone from developing testes then results in the development of other male characteristics. The absence of SRY genes or the presence of a nonfunctional SRY gene would result in the development of the fetus into a female child.

Therefore, human females have two X chromosomes as the sex chromosomes and the human males have functional SRY gene present on their Y chromosomes. Insertion of the functional SRY gene to the X chromosome of the fetus would result in its development into a male child irrespective of the absence of the Y chromosome in it.