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Germ cells migrating to the gonads may not reach that intended destination and a tumor can grow wherever they end up, but the exact cause is still unknown. These tumors can be benign or malignant. [23] On arrival at the gonad, primordial germ cells that do not properly differentiate may produce germ cell tumors of the ovary or testis in a mouse ...
Development of the gonads. The development of the gonads is part of the prenatal development of the reproductive system and ultimately forms the testicles in males and the ovaries in females. The immature ova originate from cells from the dorsal endoderm of the yolk sac. Once they have reached the gonadal ridge they are called oogonia.
Germline development in mammals. Mammalian PGCs are specified by signalling between cells (induction), rather than by the segregation of germ plasm as the embryo divides. [6] In mice, PGCs originate from the proximal epiblast, close to the extra-embryonic ectoderm (ExE), of the post-implantation embryo as early as embryonic day 6.5. [7]
Primordial germ cells are among the first lineages that are established in development [1] and they are the precursors for gametes. [2] It is thought that the process of primordial germ cell migration itself has been conserved rather than the specific mechanisms within it, as chemoattraction and repulsion seem to have been borrowed from blood cells, neurones, and the mesoderm. [1]
Chromosomal sex is determined at the time of fertilization; a chromosome from the sperm cell, either X or Y, fuses with the X chromosome in the egg cell. Gonadal sex refers to the gonads, that is the testicles or ovaries, depending on which genes are expressed. Phenotypic sex refers to the structures of the external and internal genitalia. [6]
After female (XX) germ cells collect in the undifferentiated gonads, the up-regulation of Stra8 is required for germ cell differentiation into an oogonium and eventually enter meiosis. One major factor that contributes to the up-regulation of Stra8 , is the initiation of the β-Catenin signaling pathway via RSPO1, which is also responsible for ...
The paramesonephric ducts (or Müllerian ducts) are paired ducts of the embryo in the reproductive system of humans and other mammals that run down the lateral sides of the genital ridge and terminate at the sinus tubercle in the primitive urogenital sinus. [1] In the female, they will develop to form the fallopian tubes / oviducts, uterus ...
The reproductive system begins development at four to five weeks of gestation with germ cell migration. The bipotential gonad results from the collection of the medioventral region of the urogenital ridge. At the five-week point, the developing gonads break away from the adrenal primordium. Gonadal differentiation begins 42 days following ...