The Institute for Systems Biology (ISB) and the University of Luxembourg have published an intriguing new study in the journal Science, in which they detail the genome sequencing and analysis of a family of four humans.  The sequencing marks the first time a family of four has had their genomes sequenced, and follows many individual sequencing projects over the last decade.

David Galas, PhD, a corresponding author on the paper who works at the ISB, says the work offers a glimpse of how family genome sequencing could aid in identification and understanding of disease.  He states, "We were very pleased and a little surprised at how much additional information can come from examining the full genomes of the same family.  Comparing the sequences of unrelated individuals is useful, but for a family the results are more accurate. We can now see all the genetic variations, including rare ones, and can construct the inheritance of every piece of the chromosomes, which is critical to understanding the traits important to health and disease."

Currently, genome sequencing prices have been plummeting thanks to better techniques and equipment.  In 2007, the cost was around $1M USD -- in 2008 Applied Biosystems of Foster City, California sequenced the genome of a Nigerian man for only $60,000.  In 2009, Complete Genomics, based in Mountain View, California, claimed it could read entire human genomes for $5,000.  

Nonetheless, the number of complete genomes sequenced remains relatively low.  The X Prize foundation has offered a $10M USD reward to the first person or firm that can sequence 100 human genomes in less than 10 days for less than $10,000 each.

The new sequencing project at the ISB emphasizes the benefits of sequencing for the masses.  ISB and the University of Luxembourg actually partnered with Complete Genomics to complete the sequencing.

The sequencing allowed the identification of genes related to two genetic disorders that the children had -- Miller syndrome, a rare craniofacial disorder, and primary ciliary dyskinesia (PCD), a lung disease.  In the case of Miller's syndrome, the sequencing allowed the number of candidate genes (genes that might cause the disorder) to be reduced to four.

ISB President Leroy Hood, MD, PhD, comments, "An important finding is that by determining the genome sequences of an entire family one can identify many DNA sequencing errors, and thus greatly increase the accuracy of the data.  This will ultimately help us understand the role of genetic variations in the diagnosis, treatment, and prevention of disease."

Another exciting result from the study is the first direct measurement of the intergenerational mutation rate.  The researchers found that the rate works at half the rate predicted by researchers, hinting at a potentially slower pace of human microevolution.  

Concludes Professor Galas, "This estimate could have implications for how we think about genetic diversity, but more importantly the approach has the potential to increase enormously the power and impact of genetic research.  Our study illustrates the beginning of a new era in which the analysis of a family's genome can aid in the diagnosis and treatment of individual family members. We could soon find that our family's genome sequence will become a normal part of our medical records."