Genetics research has advanced tremendously in the 21st century thanks to new technologies that have allowed scientists to analyze DNA more efficiently and gain novel insights into genetic mutations, traits, and diseases. The ability to sequence whole genomes cheaper and faster than ever before has opened up exciting new avenues for studying human genetics at both the individual and population levels. This paper will provide an overview of cutting-edge genetics research across various fields like cancer genetics, personalized genetics, medical genetics, evolutionary genetics, and more.
In cancer genetics research, next-generation sequencing technologies have allowed scientists to map the full complement of mutations present in tumor samples that drive cancer development and progression. Large-scale genome sequencing projects like The Cancer Genome Atlas (TCGA) have generated extensive catalogs of somatic mutations present in hundreds to thousands of tumor samples for over 30 different cancer types. This has revealed the core set of commonly mutated genes in each cancer along with less frequent mutations. Analyzing patterns of mutations has provided clues about the order of mutational events during tumorigenesis and highlighted previously unknown cancer genes. Such comprehensive maps of the mutational landscape of cancers are helping improve molecular classification of tumors and guiding development of targeted therapies.
At the same time, sequencing an individual’s normal DNA along with their tumor DNA allows determination of which mutations were germline or inherited from the person’s parents versus somatic or acquired only in the cancer cells. This is important for cancer genetics counseling and assessing disease risk. Finding a heritable cancer-predisposing mutation in normal DNA can indicate the need for heightened cancer screening and even preventative surgeries in some high-risk families. Projects like the 100,000 Genomes Project in the UK are comprehensively sequencing cancer patients along with their normal DNA to advance personalized cancer care and uncover more hereditary cancer syndromes.
In the sphere of personalized genetics, direct-to-consumer genetic testing services now allow individuals to gain insights into their ancestry, predisposition to certain diseases, drug responses, and traits based on variations in their DNA sequence. Large population-scale biobanks are also generating massive catalogs of genetic variants and linking them to various health-related endpoints in cohorts numbering in the hundreds of thousands of individuals. This data supports development of polygenic risk scores – statistical algorithms that combine the effects of hundreds or thousands of variants across the genome to better predict complex traits and diseases compared to single variants. Researchers are making progress in using polygenic risk scores to identify at-risk subgroups for conditions ranging from type 2 diabetes to Alzheimer’s disease to schizophrenia.
Direct-to-consumer genetic testing has furthered the field of medical genetics by helping uncover new gene-disease links. In some cases, individuals who suspected a genetic illness in their family were able to confirm the diagnosis and find other affected relatives after receiving genetic results through such services. This expanded known disease-causing gene variations in shared databases for clinical genetic testing. It has also highlighted limitations around returning pathogenic variants for untreatable disorders, variants of unknown significance, lack of informed consent for broad data sharing by some companies, and difficulties interpreting complex polygenic traits from direct-to-consumer tests. More clinical research and oversight is still needed as consumer genomics expands knowledge but also presents ethical issues.
Population-scale genetics studies have also proven very valuable for medical genetics researchers. Comparing genetic variants between groups with different disease prevalence can help identify variants contributing to each population’s disease burden. For example, projects in Africa have revealed genetic factors influencing diseases more common there like malaria, trypanosomiasis and several endemic cancers. They have shown how ancestral populations adapted genetically to endemic pathogens over centuries through natural selection on variants conferring resistance. Such studies can point to new biological pathways and drug targets relevant for those populations. Genetic diversity across global populations allows discovery of rarer but impactful variants influencing complex disease traits that may have gone undetected otherwise. Characterizing variants private to populations is also important for interpreting non-European ancestry genomes in wider biomedical research.
Studying the genetics of human evolutionary traits and adaptations has captivated researchers as well. By sequencing DNA from ancient human remains, scientists have reconstructed how modern human populations spread out of Africa and dispersed worldwide starting around 60,000 years ago. They track which mutations may have risen to high frequency and conferred benefits to ancestral populations as they encountered different environments and pathogens over the past 30,000 years since our species left Africa. Finding signals of recent natural selection in current populations has provided clues about genes influencing traits relevant to local adaptations like skin pigmentation, immunity, metabolism, salinity tolerance, altitude adaptation and more. Characterizing the genetics behind ancestral traits adapted for survival sheds light on our shared evolutionary history and provides a glimpse at how natural selection continues to shape the human genome even today.
Genetics research has come a long way from the early days of identifying the first disease genes in the 1990s. New technologies now allow us to scrutinize the genome on an unprecedented scale to better understand the genetic contributions to both rare hereditary disorders and common complex diseases. Research efforts spanning cancer, ancestry, personalized disease risk profiles, population diversity, evolution and more continue to propel discovery science and translate findings into clinical applications like precision medicine approaches. Large international collaborations increasingly combine datasets to achieve larger sample sizes and find effects that would otherwise go undetected. Continued open data access and global participation will be key to maximizing the potential of human genetics to improve lives worldwide. With rapidly evolving tools, the future promises further breakthroughs across all domains of human genetics.
Andrew Stroud