{"id":9051,"date":"2019-05-22T16:14:23","date_gmt":"2019-05-22T16:14:23","guid":{"rendered":"http:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/sex_chromosomes\/"},"modified":"2019-05-22T16:14:23","modified_gmt":"2019-05-22T16:14:23","slug":"sex_chromosomes","status":"publish","type":"post","link":"https:\/\/www.lancaster.ac.uk\/fas\/psych\/glossary\/sex_chromosomes\/","title":{"rendered":"Sex chromosomes"},"content":{"rendered":"

The genetic material that determines whether one develops male or female reproductive structures. It humans, it is typically XX for female and XY for male.  The short squat Y chromosome, containing only 20 genes compared to more than 1000 for the X chromosome, has been depicted as doing little more than determining the sex of the fetus  This view has been challenged recently in Swiss-based<\/a> and US-based<\/a> studies using different genetic sequencing methods, but arriving at similar findings.  Based on cross-species comparisons, it appears that appears that the first sex chromosomes were established 180 million years ago, the Y chromosome not existing before that date.  The determinants for their appearance are still unclear, but may have been due to the environmental influences such as temperature (e.g., as in the case of crocodiles).  Whatever the case, there has been a considerable Y chromosome ‘shrinkage’, with genes remaining because of their crucial survival functions.  On such broad function includes controlling the expression of genes in many other areas of the genome.  Moreover, genes on the Y chromosome often vary slightly in sequence from corresponding genes on the X chromosome, thus giving rise to different patterns of gene expression throughout the body compared to females.  On this basis, it is speculated that such a finding could account for differences in disease susceptibility between males and females.       <\/p>\n

See Chromosome<\/a>, Gene<\/a>, Genome<\/a>, Sex<\/a>, Sex ratio<\/a>, Spermatozoa<\/a><\/p>\n

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The genetic material that determines whether one develops male or female reproductive structures. It humans, it is typically XX for female and XY for male.  The short squat Y chromosome, containing only 20 genes compared to more than 1000 for the X chromosome, has been depicted as doing little more than determining the sex of … <\/p>\n

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