Metaphors for human fertilization are evolving, study shows

In a common metaphor used to describe human fertilization, sperm cells are competitors racing to penetrate a passive egg. But as critics have noted, the description is also a "fairy tale," rooted in cultural beliefs about ...

Determining the tempo of evolution across species

Scientists from Denmark and China have estimated germline mutation rates across vertebrates by sequencing and comparing genetic samples from 151 mother, father, and offspring trios from 68 species of mammals, fishes, birds ...

Rewiring blood cells to give rise to precursors of sperm

Different cell types—say, heart, liver, blood, and sperm cells—possess characteristics that help them carry out their unique jobs in the body. In general, those characteristics are hard-wired. Without intervention, a ...

page 1 from 15


A gamete (from Ancient Greek γαμέτης; translated gamete = wife, gametes = husband) is a cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete — called an ovum (or egg) — and a male produces the smaller tadpole-like type — called a sperm. This is an example of anisogamy or heterogamy, the condition wherein females and males produce gametes of different sizes (this is the case in humans; the human ovum is approximately 20 times larger than the human sperm cell). In contrast, isogamy is the state of gametes from both sexes being the same size and shape, and given arbitrary designators for mating type. The name gamete was introduced by the Austrian biologist Gregor Mendel. Gametes carry half the genetic information of an individual, one chromosome of each type. In humans, an ovum can carry only X chromosome (of the X and Y chromosomes), whereas a sperm can carry either an X or a Y; hence, it has been suggested that males have the control of the sex of any resulting zygote, as the genotype of the sex-determining chromosomes of a male must be XY and a female XX. In other words, due to the presence of the Y chromosome exclusively in the sperm, it is that gamete alone that can determine that an offspring will be a male.

This text uses material from Wikipedia, licensed under CC BY-SA