Visual phasing is a technique developed by Kathy Johnston that allows to assign DNA segments of three full siblings to all their four grandparents by comparing their crossing-over points.
What are the requirements?
- autosomal DNA raw data files of the three full siblings (or more) uploaded to GEDmatch
- multiple 2nd or 3rd cousins on several ancestral lines available for comparison
- Steven Fox’s automated Excel spreadsheet (available for download at the Visual Phasing working group on Facebook)
- advanced understanding of genetic genealogy
- analytical skills and patience