Is sex primarily a strategy against transmissible cancer?

One of the greatest enigmas of evolutionary biology is that while sex is the dominant mode of reproduction among multicellular organisms, asexual reproduction appears much more efficient and less costly. However, in a study ...

Robots to the rhino rescue

The critically endangered northern white rhino might have more of a chance thanks to a partnership between the University of California San Diego and San Diego Zoo Global.

Fluconazole makes fungi sexually active

The yeast Candida albicans occurs in most healthy people as a harmless colonizer in the digestive tract. However, it can also cause life-threatening infections, especially in immunocompromised patients.

Sex or food? Decision-making in single-cell organisms

Unicellular diatoms are able to adapt their behavior to different external stimuli based on an evaluation of their own needs. This was discovered by scientists of the Friedrich Schiller University and the Max Planck Institute ...

How do jumping genes cause disease, drive evolution?

Almost half of our DNA sequences are made up of jumping genes—also known as transposons. They jump around the genome in developing sperm and egg cells and are important to evolution. But their mobilization can also cause ...

Digging deep into distinctly different DNA

A University of Queensland discovery has deepened our understanding of the genetic mutations that arise in different tissues, and how these are inherited.

Bridging tumor moats with potent drug delivery particles

Despite herculean efforts, cancer remains a formidable disease, with each malignant subtype responding differently to therapeutics. One hurdle specific to treating solid tumors is a protective layer called an extracellular ...

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Gamete

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.

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