Chromosomes are tightly packaged bundles of DNA, the chemical that encodes genetic information.
Most of the cells in a human body have a set of 46 chromosomes in their nucleus, while egg and sperm cells have only 23.
Separately, each of the mitochondria in each cell of a human body contain their own DNA, in the form of (multiple copies of) a circular chromosome.
The Human Fertilisation and Embryology Authority (HFEA) is likely to approve the genetic screening of in vitro fertilisation (IVF) embryos in the UK. Screening embryos for genetic abnormalities may help fertility doctors decide which embryos are best to implant into the uterus of women receiving treatment. The success rate of...
Scientists at the University of Pittsburgh, US, have identified a small section of DNA, a 'genetic marker', which may point to a significantly increased risk of the development of Alzheimer's disease. Ten years was spent studying 300 relatives of 189 people who had developed the disease. It was found that...
Scientists from the US National Institute of Mental Health (NIMH) have found a gene variation that may increase the risk of developing schizophrenia. The gene, called COMT (catecho-o-methytransferase) appears to control levels of the chemical dopamine in the brain. Lower levels of dopamine can affect performance in memory tasks and...
Two teams of researchers, in the US and in France, have pinpointed a gene which is involved in some cases of Crohn's disease, an inflammatory disorder of the gastrointestinal system. The research, published in the journal Nature, shows how a gene on chromosome 16 codes for a protein called NOD2...
The controversial program using cytoplasmic transplantation - adding cytoplasm from the egg of a healthy donor woman to that surrounding the nucleus of an infertile woman's egg - has been further criticised this week after it was disclosed that two of the babies created had genetic abnormalities. Although it was subsequently shown...
A gene that is involved in the sex determination of fetuses can also cause serious genital malformations in babies. Scientists have discovered malformations can occur in babies born with more than two copies of the WNT-4 signalling gene. Most people have two copies of the gene which is found...
The UK Government has been told by the Wellcome Trust, the world's biggest biomedical charity, to pay for research facilities for British scientists or Britain will be relegated from the research 'Premier League'. The trust seems to be showing that it is tired of 'making up shortfalls' in state investment...
German scientists at the University of Wurzburg believe that they have found the gene responsible for an inherited form of schizophrenia. There have been many previous claims about genes linked to schizophrenia and other behavioural disorders, but this is believed to be the first genuine genetic basis to the disease...
A lack of folic acid in the diet could be responsible for some cases of male infertility, according to new research presented at a conference in Lyons last week. Professor Bruce Ames of the University of California told delegates at the World Life Sciences Forum that sperm counts in rats...
The head of the Centres for Assisted Reproduction at the Park Hospital in Nottingham has accused the UK's Human Fertilisation and Embryology Authority (HFEA) of excessive caution, over its likely refusal to grant him a license to carry out trials of a new embryo screening technique. Dr Simon Fishel told...
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