Biology Chapter 6: Sex Determination & Gametogenesis

The process by which genetic factors (chromosomes) determine whether an embryo develops into a male or a female.

In mammals, the presence of a Y chromosome usually leads to the development of testes.

In mammals, the presence of two X chromosomes usually leads to the development of ovaries.

The initial stage of a developing gonad in a mammal that can develop into either testes or ovaries depending on genetic factors.

The process of forming gametes (sperm and eggs).

The process of forming sperm cells.

The process of forming egg cells.

Chromosomes that determine the sex of an organism.

A mechanism where environmental factors (like temperature during embryonic development) influence the sex of an organism.

A mechanism where the sex of an organism is determined by the combination of sex chromosomes present.

The process by which the sex of a mammal is determined, primarily based on the presence or absence of a Y chromosome, which initiates testis development.

The Y chromosome triggers the development of testes, leading to the male sexual phenotype regardless of the number of X chromosomes.

A genetic condition characterized by the presence of only one X chromosome, resulting in underdeveloped female external genitalia.

A genetic condition with an extra X chromosome and a Y chromosome, leading to the development of testes but with lower androgens and higher estrogens, often causing infertility.

The initial determination of sex based on the gonads (testes or ovaries).

The development of sexual characteristics outside the gonads, including the reproductive ducts and external genitalia, influenced by hormones and factors produced by the gonads.

The chromosomes that determine the sex of a mammal – either XY (male) or XX (female).

Having an unusual number of sex chromosomes (e.g., XXX, XXY, XYY, XO).

The initial process of determining whether an embryo develops into a male or female.

An embryonic structure that in the presence/absence of specific genes (and Y chromosome) forms different gonads (ovaries or testes)

An embryonic structure that has the potential to develop into either a testis or an ovary.

A gene located on the Y chromosome that triggers testis development

A transcription factor activated by Sry that is crucial for testis development.

Two genes that trigger ovarian development in XX embryos preventing Sox9 activation.

A protein that, when activated, promotes ovarian development and inhibits testis development.

The process of deciding between XX (Female) / XY(Male) development, driven by respective genes.

The usual genetic makeup of a female, indicating two X chromosomes.

The usual genetic makeup of a male, indicating two sexes

Development of sex characteristics like breasts or genitalia.

Cells in the testes that produce testosterone.

Cells in the testes that produce AMH.

A condition where XY individuals don't respond to testosterone.

Hormone that causes Mullerian duct degeneration.

Ducts that develop into male internal structures if stimulated by testosterone.

Ducts that develop into female internal structures if not inhibited by AMH.

A condition where testosterone can't be converted to DHT.

Hormone that promotes male external genitalia development.

Estrogen's role in developing female reproductive organs and external genitalia in XX individuals.

Estrogen is crucial for reproductive development in both males and females.

Absence of estrogen receptors leads to significant reproductive issues in both male and female mice.

A process that equalizes gene expression between males and females with two X chromosomes.

The inactive X chromosome condensed into a dense structure in the cell's nucleus.

The coat color pattern in calico cats is due to random X chromosome inactivation.

Sry, a gene found only in mammals, activates the Sox9 transcription factor, initiating testis development.

Sox9, a transcription factor present in all vertebrates, promotes testis formation by regulating genes involved in male development.

The SRY gene is the main trigger for mammalian male sex development; in the absence of SRY, female development is more likely to occur.

Even with two X chromosomes (XX), if SRY is present from any other source (e.g translocation or duplication of SOX9), testes formation is triggered.

Without SRY in XX individuals, female development occurs due to lack of male-promoting factors.

Mutation or deletion of the SRY gene on the Y chromosome results in female development despite having a Y.

Following gonad formation, hormones regulate the development of secondary sexual characteristics (e.g., reproductive organs and physique).

A duct system in an embryo that develops into female reproductive tract parts (oviducts, uterus, etc.), maintained by estrogen.

A duct system in an embryo that develops into male reproductive tract parts maintained by testosterone secreted by testes.