Blog

  • IBD sharing rates across length thresholds
    Some time ago, we received a request in response to our sharing rate plots for relatives with ≥ 7 cM segments to also plot rates for ≥ 5 cM segments. Instead of just calculating the rates for one more threshold, it seemed good to include several different lengths. Thus we now have a IBD sharing […]
  • Reconstructing DNA from one parent with HAPI
    For RootsTech Connect this past week, we released the tool HAPI, which reconstructs DNA for one parent using data from three or more children and their other parent. Two videos from RootsTech describe ancestor DNA reconstruction in general and the HAPI tool in particular. This post briefly reviews the video about HAPI and then goes […]
  • Minimal viable genetic maps
    In our first blog post on what is a centiMorgan?, we talked about genetic maps. Many of the planned tools at HAPI-DNA (and all of the current ones) use genetic maps to calculate lengths of segments or to simulate segments. One of the most commonly used genetic maps (the HapMap map) contains nearly 3.4 million […]
  • How often do two half relatives share DNA?
    Following up on the last post about full relatives, the plot below shows the rates that half relatives share ≥ 7 cM IBD segments. This uses the same abbreviations as in the previous post—1C means first cousins, 3C1R stands for third cousins once removed—but all relationships are prefixed with an `h’ for half. The first […]
  • How often do two relatives share DNA?
    Close relatives like two full siblings, an aunt and nephew, or a grandparent and grandchild always share IBD segments, so they show up in testing companies’ relative matches. However, more distant relatives may not share any IBD segments. In fact, the chance that two people share DNA decreases with the distance of their relationship. This […]