Sperms make humans prone to cancer
Jun 13, 2005
The evolutionary path that separated human beings from chimpanzees five million years ago may have made human sperm survive better, but may have made humans prone to cancer.
The evolutionary path that separated human beings from chimpanzees five million years ago may have made human sperm survive better, but may have made humans prone to cancer.
A comparison of chimpanzee genes to human genes shows a concentration of genes unique to people in areas associated with sperm production and cancer, suggesting the changes that make humans unique also make us uniquely prone to cancer.
“This may explain the high prevalence of cancer,†said Rasmus Nielsen of the University of Copenhagen in Denmark, who led the study while at Cornell University in New York.
The team studied the chimpanzee genome, the collection of all DNA to find out what makes chimps and humans different. They knew genes having to do with smell, making sperm and fighting bacteria and viruses were likely to be different.
“However, we were surprised to find a large proportion of cancer-related genes that may be related to tumour development and control,†they wrote.
In cancer, cells lose their ability to self-destruct when they become faulty, a process called apoptosis. Cell cycling, the process by which cells activate, divide and grow into two separate cells, is also disrupted in cancer.
“Eliminating cancer cells by apoptosis is one of the main processes to fight cancer,†Nielsen said.
“The connection we saw is that these genes involved in proliferation may be involved in spermatogenesis,†Cornell’s Andrew Clark said.
Apoptosis also kills many sperm cells before they mature. But evolution could have interfered with this process, allowing more sperm to reach maturity, thus carrying the mutation into the next generation.
Cancer in people usually occurs in late adulthood, after they have reproduced and thus has not been removed by natural selection.
Reuters
A comparison of chimpanzee genes to human genes shows a concentration of genes unique to people in areas associated with sperm production and cancer, suggesting the changes that make humans unique also make us uniquely prone to cancer.
“This may explain the high prevalence of cancer,†said Rasmus Nielsen of the University of Copenhagen in Denmark, who led the study while at Cornell University in New York.
The team studied the chimpanzee genome, the collection of all DNA to find out what makes chimps and humans different. They knew genes having to do with smell, making sperm and fighting bacteria and viruses were likely to be different.
“However, we were surprised to find a large proportion of cancer-related genes that may be related to tumour development and control,†they wrote.
In cancer, cells lose their ability to self-destruct when they become faulty, a process called apoptosis. Cell cycling, the process by which cells activate, divide and grow into two separate cells, is also disrupted in cancer.
“Eliminating cancer cells by apoptosis is one of the main processes to fight cancer,†Nielsen said.
“The connection we saw is that these genes involved in proliferation may be involved in spermatogenesis,†Cornell’s Andrew Clark said.
Apoptosis also kills many sperm cells before they mature. But evolution could have interfered with this process, allowing more sperm to reach maturity, thus carrying the mutation into the next generation.
Cancer in people usually occurs in late adulthood, after they have reproduced and thus has not been removed by natural selection.
Reuters