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In species that use the XY sex-determination system, parthenogenetic offspring have two X chromosomes and are female. In species that use the ZW sex-determination system the offspring genotype may be one of ZW (female), [28] [29] ZZ (male), or WW (non-viable in most species, [31] but a fertile, [dubious – discuss] viable female in a few, e.g ...
Androgenesis is a system of asexual reproduction that requires the presence of eggs and occurs when a zygote is produced with only paternal nuclear genes.During standard sexual reproduction, one female parent and one male parent each produce haploid gametes (such as a sperm or egg cell, each containing only a single set of chromosomes), which recombine to create offspring with genetic material ...
The female boa could have chosen any number of male partners (and had successfully in the past) but on this occasion she reproduced asexually, creating 22 female babies with WW sex-chromosomes. Polyembryony is a widespread form of asexual reproduction in animals, whereby the fertilized egg or a later stage of embryonic development splits to ...
In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also known as the SRY gene. [5] Thus, male mammals typically have an X and a Y chromosome (XY), while female mammals typically have two X chromosomes (XX).
In some species, there are hermaphrodites, i.e., individuals that can function reproductively as either female or male. [2] There are also some species in which only one sex is present, temporarily or permanently. This can be due to parthenogenesis, the act of a female reproducing without fertilization.
If a male offspring is produced, the gene will consist of an X and a Y chromosome, and if a female offspring is produced, the gene will consist of two X chromosomes. [3] Cloning is the production of an offspring which represents the identical genes to its parent. Reproductive cloning begins with the removal of the nucleus from an egg, which ...
In the XY sex-determination system, the female-provided ovum contributes an X chromosome and the male-provided sperm contributes either an X chromosome or a Y chromosome, resulting in female (XX) or male (XY) offspring, respectively. Hormone levels in the male parent affect the sex ratio of sperm in humans. [25]
Sexual reproduction typically requires the sexual interaction of two specialized reproductive cells, called gametes, which contain half the number of chromosomes of normal cells and are created by meiosis, with typically a male fertilizing a female of the same species to create a fertilized zygote. This produces offspring organisms whose ...