Sex Wars

PERPETUAL ICE (Interlocus Contest Evolution) 

‘Ever since the evolution of sexual differentiation in mammals is thought to have started when one of a pair of chromosomes picked up a gene that gave males a selective advantage, the sex chromosomes have been at war. As the sex chromosomes diverged over time, the Y chromosome lost the ability to recombine - its genes that are not essential have accumulated mutations and either been shut down or lost, the Y chromosome is reduced to a stump, clinging onto the genes that offer males a competitive advantage, and expressing only some of the genes it does have.  In some cases, genes on the Y chromosome may be detrimental to females. By residing on the Y, however, they can survive - as they never occur in females, they can escape being discarded by the selective forces acting in the interests of females. By improving the fitness of males that carry them, they wage their own battle in the ongoing conflict between the sexes. A DNA map of the Y chromosome shows that it includes large repeated chunks, termed ‘amplicons’, which are so similar that they are almost impossible to tell apart. Many of the male-specific genes lie in these regions, such as those involved in testes development and sperm production, and it is possible that this duplication is an attempt to ensure that the genes aren’t lost in the battle with the X (safety in numbers!)’ Wellcome Trust, 2001

‘In our case, the sex determining gene made us male and the lack of it female, whereas in birds it happened the other way round. The gene soon attracted to its side other genes that benefited males: genes for big muscles, say, or aggressive tendencies. But because these were no wanted in females – wasting energy they would prefer to spend on offspring – these secondary genes found themselves at an advantage in one sex and at a disadvantage in the other. They are known in the trade as sexually antagonistic genes. The dilemma was solved when another mutant gene suppressed the normal process of swapping genetic material between the two paired chromomsomes. Now the sexually antagonistic genes could diverge and go their different ways.. thus, a pair of middle sized chromosomes, once home to all sorts of ‘norma’ genes, was hijacked by the process of sex determination and became the sex chromosomes, each attracting different sets of genes. On the Y chromosome, genes accumulate that benefit males but are often bad for females; on the X accumulate genes that are good for females and deleterious in males…. This outbreak of antagonism between genes is a dangerous situation…. the two chromosomes no longer have each other’s interests at heart, let alone those of the species as a whole.’ Matt Ridley, Genome: The Autobiography of a Species in 23 Chapters, Fourth Estate, 2000

Man is an alteration to the chemistry

In the beginning, we are female -

woman is first; man an alteration

to the chemistry - intensification,

focus on core male; retreat, siege

against the female - her revelling

in life, emotional room; gendered

choice in what constitutes value,

importance in life’s perspective.

Are men not more primitive, simple -

still locked in a struggle for survival

that no longer exists, has been civilised;

clinging to bare reproductive essentials,

while heart and eyes stumble,

grudging luxury and comfort -

still hunting in the supermarket age,

on Saturday nights in pub jungles –

drunk, unloosened - under mannered

veneers of millennia where the genes

will be king; the young males practically

beating their chests, hollering, whooping

like gorillas - rugger buggers butting -

steaming, displaying, like rutting stags.

Note from the author
exploring the project

    Gene Story
    Romantic Science
    Some Special Genes
    X & Y
        Y Chromosome
        SRY Gene – Master Switch
        Sex Wars
        X Chromosome
        Some notes on the
        Gender of Science

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