In October 2025, MyHeritage introduced the first low pass whole genome (LP-WGS) DNA test tailored for and focused exclusively on genetic genealogy. This replaces previous autosomal tests, but the results are compatible, protecting earlier testers’ investments.
Research your ancestors on MyHeritage
How did we get here?How did we get here?
Industry-wide, previous autosomal tests have utilized custom global screening array (GSA) microarray chips[1] that target about 700,000 locations, or addresses, in the human genome. The goal, of course, is to use regions of the human genome most prone to accumulating mutations for comparison with other testers to identify unique matching sequences inherited from specific ancestors. Many DNA segments above a minimum size of about 8 centiMorgans (cM)[2] passed down over the generations to present-day testers match other testers because they are inherited from common ancestors in the relatively recent past, generally within 8 or 9 generations.[3]
These GSA tests are readily available, and customizable by vendors, costing less than $100 to the consuming public. Each testing company selects around 500,000 of the same locations, but can also customize their test by selecting another ~200,000 locations that they believe are beneficial for their purposes or products. The vendor may use these to target specific locations for Y-DNA or mitochondrial DNA haplogroups, or additional autosomal locations for features such as health or other traits. Hence, different tests on different chips are never fully compatible, requiring a process called imputation to level the playing field when comparing DNA results from different chips – including different chips or chip configurations used by the same vendor at different points in time.
ImputationImputation
Imputation is a scientific method of filling in relatively small blank portions of DNA that is missing. Think of the English word “cat.” If the middle letter is missing, we have c_t. The missing letter is most likely either an “a”, “o”, or “u.” When read in context of the sentence, “The c_t jumped over the leaf,” the only reasonable answer is “a” for “cat.” That’s the same thing that imputation does for missing “letters” of DNA. The genetic string is read in context of its neighboring nucleotides,[4] or genetic letters, and the most likely result is inserted into the “blank” space.
Visually, one can think of a 700,000-location GSA test as a machine with 700,000 fluorescent probes that specifically target those selected addresses in our DNA. The result is our haplotype, or individual results, which can be found in our DNA download file. The testing vendor compares the DNA results to other testers in their database, searching for matching DNA segments over a specific size threshold. The larger the amount of matching DNA, the more closely related the two people are. If the DNA files being compared were processed on different chips, or uploaded from another vendor, they are imputed to a common set of markers before comparison occurs.
How Does Whole Genome Sequencing work?How Does Whole Genome Sequencing work?
Whole genome testing is a different type of DNA test. Instead of targeting specific locations and only testing for the contents of those locations, whole genome testing scans the entire human genome, hence, the name “whole genome sequencing,” abbreviated as WGS. Think of a drone flying over and taking photos of an entire landscape from the air, instead of targeting only specific street addresses. WGS tests scan nearly all 3.2 billion locations in the entire human genome, recording the nucleotide value inherited from both parents stored at each location.
Not all whole genome tests are created equal, though. The most comprehensive and equivalently expensive are WGS clinical-grade medical tests run in specialty laboratories. Typical medical tests scan the genome between 30 and 50 times, written as 30x and 50x, which is referred to as sequence depth. Even higher depth whole genome sequencing, 100x or greater, is employed in research environments that are looking for very rare single mutations and are specifically used in cancer research.[5]
Because WGS is a scan, not every location will be read with each pass, so the combination of multiple passes greatly increases the probability that every location will be successfully read, multiple times for clinical-grade tests, even if some reads are missing in some scan passes. Specialized software reassembles data from multiple passes, aligning locations with genetic landmarks, known as seed sequences, so that results at any location can be confirmed across multiple reads.[6] High pass or high coverage whole genome sequencing is expensive to process and has substantial storage requirements, beginning at about 100 GB of space per test.
MyHeritage has adopted the CRAM file format[7] for their LP-WGS test, which significantly drops the storage requirement, and therefore the cost of each test. The tester’s results are compared to a genetic reference sequence, and only the genetic differences are stored in CRAM files, as opposed to the value at every location. The human genome is 99.9% identical among all people,[8] and there is no value in storing all of those identical locations. The high cost of processing and storage had traditionally placed WGS tests outside the affordable range for genealogy testing.
The Affordability barrier is brokenThe Affordability barrier is broken
The affordability barrier was broken by recent advances in low pass whole genome (LP-WGS) wafer-based testing developed in a three-way partnership between MyHeritage,[9] Ultima Genomics,[10] and Gene by Gene.[11] This liaison offers both leading-edge technology and accuracy at a price comparable to or even less than legacy GSA tests. MyHeritage has combined 2x low-pass whole genome testing with imputation, where locations missed by both passes are scientifically imputed based on known genomic sequence combinations.
In addition to reducing the cost of whole genome sequencing, LP-WGS provides backward compatibility with existing platforms and GSA-based files, and paves the way for the future, allowing MyHeritage to begin the process of identifying additional useful locations and building a library of testers to be compared in the future. This approach provides testers with both backwards compatibility and a portal to the future - the best of both worlds.
See alsoSee also
Explore more about Whole Genome SequencingExplore more about Whole Genome Sequencing
- MyHeritage Upgrades Its DNA Tests to Whole Genome Sequencing on the MyHeritage blog
References
- ↑ Infinium™ Global Screening Array-24 v3.0 BeadChip. Illumina
- ↑ Major Updates and Improvements to MyHeritage DNA Matching. MyHeritage blog
- ↑ DNA Explained: What Can It Tell You About Your Ancestry. MyHeritage blog
- ↑ Nucleotide. NIH
- ↑ Optimizing Cancer Genome Sequencing and Analysis. Cell Systems
- ↑ Whole-Genome Alignment and Comparative Annotation. National Library of Medicine
- ↑ CRAM. Sanger Institute
- ↑ Genetics by the Numbers. NIH
- ↑ MyHeritage Upgrades Its DNA Tests to Whole Genome Sequencing. MyHeritage blog
- ↑ Paired plus-minus sequencing is an ultra-high throughput and accurate method for dual strand sequencing of DNA molecules. Biorxiv
- ↑ MyHeritage Upgrades Its Consumer DNA Tests to Whole Genome Sequencing. Businesswire