Researchers analysed thousands of laboratory-made plasmids and discovered that nearly half of them had defects, raising questions of experimental reproducibility.
CGS-authored
A personal DNA test that has sparked controversy in the US has launched in the UK.
The UK's Medicines and Healthcare Products Regulatory Agency (MHRA) says the 23andMe spit test, which is designed to give details about a person's health risks based on their DNA, can be used with caution.
But critics say it may not be accurate enough to base health decisions on.
The company, California-based 23andMe, stands by its test.
Backed by Google, the firm offered US customers details of health risks based on gene variants they carry.
But in November 2013, the US Food and Drug Administration (FDA) banned the company from marketing its service in the US, claiming 23andMe had failed to provide adequate information to support the claims it made about results.
A month later, the company stopped offering genetic tests related to health.
'Think carefully'An MHRA spokesperson said it regulated such tests in the UK to make sure they met minimum standards.
"People who use these products should ensure that they are CE marked and remember that no test is 100%...