It will be hard to capture all of the discoveries that have been made and posted at this site in the past twelve months. A year ago I was using a very basic natural model of genetic inheritance. I had been publishing averages and ranges of shared DNA for relationships…

Relationship predictions are now updated to include differences in maternal and paternal recombination rates as well as validation of ranges by peer-reviewed standard deviations — The calculator can be found here. I’ve previously published exact averages and very accurate ranges of shared DNA for any genealogical relationship that can be imagined. The model that produces these results is validated by the standard deviations of Veller et al. (2019 & 2020). …

How much of an ancestor’s or relative’s DNA can you reproduce when you combine kits of multiple testers? — I wrote the original article on DNA coverage from multiple kits a few years ago. I included tables that showed the amount of an ancestor’s autosomal DNA you could reproduce if you combined kits from multiple relatives. In those tables were exact averages and approximate ranges. …

Alternate title/misleading answer: 23andMe counts FIR twice — Scientists who aren’t familiar with genetic genealogy will be very confused by this question. After all, 50% is the expected amount, or average, that two siblings share. People asking this question have likely been trapped inside of an AncestryDNA bubble. AncestryDNA doesn’t report the amount of fully-identical regions (FIR) that…

People often ask a question similar to this one: If my ethnicity report is showing 5% Iberian, how far back should I expect to find an ancestor of mine who was Iberian? There’s a mathematical way to estimate the answer to that question. …

People often ask how their DNA match with a cousin will be inflated if they have a double relationship with that cousin. Some helpful people have offered that you can look up shared averages and ranges for certain relationships and double all of them, or for two different types of…

Using very simple math the get to most out of multiple kits — Many genetic genealogy enthusiasts have their own DNA genotyped as well as some of their siblings. As the enthusiast of your family, you might have access to all of these kits. Or, if they’re all on GEDmatch.com, then you can use these kits in tools whether or not you’re the…

The only cousin statistics that acknowledge the differences in paternal and maternal relatives due to recombination rates. — The average recombination rate in mothers is about 42. Conversely, genomes in fathers only recombine about 27 times, on average. This leads to a conclusion that’s intuitive to geneticists: More recombination decreases variance, leading to narrower ranges in shared DNA for maternal relatives. Less recombination results in more variance, which…

A comparison of three models, including updated amount of shared DNA between various relatives and ancestors — Genetic Modeling Background I recently published a comparison of autosomal genetic models. The first model, which I made about two years ago, is as simple as can be, but I think it captures the important insights. The new model adds the feature of two homologues per chromosome that you’d find…