Related topics: genes

Snake sex chromosomes say less about sex and more about survival

Sex-specific chromosomes are a dangerous place to be, if you're a gene. Because these chromosomes—Y chromosomes, in humans—do not have a matching chromosome with which to exchange genetic information, they are prone to ...

How Earth's oddest mammal got to be so bizarre

Often considered the world's oddest mammal, Australia's beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs ...

The birth of a male sex chromosome in Atlantic herring

The evolution of sex chromosomes is of crucial importance in biology as it stabilizes the mechanism underlying sex determination and usually results in an equal sex ratio. An international team of scientists, led by researchers ...

Why the 'wimpy' Y chromosome hasn't evolved out of existence

Much smaller than its counterpart, the X chromosome, the Y chromosome has shrunken drastically over 200 million years of evolution. Even those who study it have used the word "wimpy" to describe it, and yet it continues to ...

When determining sex, exceptions are the rule

For nearly a century, biologists have modeled the evolution of sex chromosomes—the genetic instructions that primarily determine whether an individual will develop into a male or female (or a certain mating type)—resulting ...

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Sex-determination system

A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most sexual organisms have two sexes. In many cases, sex determination is genetic: males and females have different alleles or even different genes that specify their sexual morphology. In animals, this is often accompanied by chromosomal differences. In other cases, sex is determined by environmental variables (such as temperature) or social variables (the size of an organism relative to other members of its population). The details of some sex-determination systems are not yet fully understood.

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