genetics

An international team of scientists, including researchers from the CRG and the CNAG (Barcelona), have managed to recover DNA remains from a female woolly mammoth that died in Siberia 52,000 years ago. The novelty is that, for the first time, the remains conserve the three-dimensional structure in the form of chromosomes, which makes it possible to investigate the genes that were active. According to one of the authors of the study, the results of which are published in the journal Cell, this type of discovery "changes the rules of the game, because knowing the shape of the chromosomes of an organism allows us to assemble the entire DNA sequence of extinct creatures and obtain information that was not possible before".

In a new study in mice published in Science, researchers present CHARM, an epigenetic editor that can be used to silence prion protein throughout the brain. The tool offers a path to effective first-line treatment for patients with fatal prion diseases, as well as other neurodegenerative diseases caused by the toxic accumulation of unwanted proteins. 

Two articles published in Nature describe a new genome editing technique that enables the insertion, inversion, or deletion of long DNA sequences at specific positions in the genome. This is a one-step approach that could offer a simpler method for genome editing in the future. The authors describe a technique to create reprogrammable recombinases—key enzymes in genetic recombination. These enzymes are guided by RNA, which acts as a bridge, directing the recombinase to target sites and facilitating predetermined editing.

About one in 5,000 people have a genetic variant in the SMIM1 gene that results in a particular type of blood type called Vel negative. An international team of researchers now describes the same variant as being associated with a predisposition to obesity, metabolic disturbances and lower resting energy expenditure. Women studied with the variant weigh, on average, 4.6 kg more, while in men the difference is about 2.4 kg. The results are published in the journal Med, published by the Cell group. 

The classical view describes most cancers as the result of mutations that happen by chance and accumulate over a lifetime. Now, a study claims to break that paradigm. A team of researchers from Stanford University (USA) has described that the genetics we inherit influences the surveillance that our defences do of these mutations, conditioning the type of tumour that can develop and its prognosis. The results, which for the moment refer to breast cancer, are published in the journal Science.  

Genetic forms of Alzheimer's are considered to be those in which certain variants of a gene inevitably lead to the disease over time. Until now, only rare alterations in three genes were considered as such. A group of researchers led by the Hospital de Sant Pau in Barcelona has proposed a new, much more frequent form. After analysing data from more than three thousand donated brains and clinical data from more than ten thousand patients, they found that almost all people who carry two copies of the ApoE4 variant in the ApoE gene, which was previously only considered a risk factor, also end up developing the disease.They publish the results in the journal Nature Medicine.  

10 % of people are left-handed, which occurs when the right cerebral hemisphere is more dominant for the control of that hand - whereas it is the left hemisphere in the case of right-handed people. To investigate the genetic basis of this laterality, scientists in the Netherlands have analysed genome data from 350,000 people in the UK biobank for rare genetic variants associated with this phenomenon. The heritability of left-handedness due to rare coding variants was low, at less than 1%. The research, published in Nature Communications, suggests that one gene - TUBB4B - is 2.7 times more likely to contain rare coding variants in left-handed people. 

An international team of researchers has examined the epigenetic effects of tobacco and e-cigarettes over time in more than 3,500 samples. Their results indicate that e-cigarettes can also cause changes associated with an increased risk of cancer even shortly after starting to use them. They publish the study in the journal Cancer Research. 

Sperm from older fathers are more likely to pass on new mutations that would cause congenital disorders to their babies, while other mutations are independent of paternal age, says a study published in Genome Biology and Evolution. The team analysed the frequency of ten FGFR3 gene variants in semen samples from anonymous donors aged 23-59 years in Austria. Two pathogenic mutations of this gene do occur more frequently in older fathers: those associated with achondroplasia and with thanatophoric dysplasia, a rare and very fatal disease. Other mutations have no correlation with paternal age and may occur in the testes before sexual maturation, according to the study.

People with Down syndrome often have heart problems, which can affect their life expectancy. However, the genes responsible among the 230 possible candidates were not known. A team of researchers used human tissue and mouse embryonic hearts and concluded that an extra copy of the DYRK1A gene is important in the process. In addition, they have tested a treatment in early gestation in mouse models that reduces its consequences. The research is published in Science Translational Medicine.