**GENEALOGY-DNA-L Archives**

From:Obed W Odom <>Subject:Re: [DNA] D Faux's cousinsDate:Sat, 03 Dec 2011 11:30:15 -0600References:<mailman.175.1322869475.20702.genealogy-dna@rootsweb.com><C943924D-B236-4D5B-8979-68F9EA2052B9@charter.net><4EDA4AD5.5000901@mail.utexas.edu>In-Reply-To:<4EDA4AD5.5000901@mail.utexas.edu>In my previous post (below) I think I overestimated the chance of *both*

siblings having no crossover on any of their 44 autosomes. The number I

gave, (1/2)exp44, was the chance of one of the siblings having no

crossover, so the chance of both siblings having no crossover would be

(1/2)exp88, making the odds of 2 siblings sharing zero segments

(1/2)exp132, or only 1 out of 5445 trillion trillion trillion.

On 12/3/2011 10:14 AM, Obed W Odom wrote:

> The odds of 2 true siblings sharing zero segments would certainly be

> less than (1/2)exp44, or 1 out of 17.6 trillion. This number assumes no

> crossing over between homologous chromosomes. If one assumes that for

> each autosomal chromosome pair there is a 50% chance of having no

> crossover, then the chance of having no crossover on *any* of the 44

> inherited autosomal chromosomes would again be (1/2)exp44, making the

> odds of 2 siblings sharing zero segments (1/2)exp88, or 1 out of 309

> trillion trillion, a truly vanishingly small number.

>

**This thread:**

- Re: [DNA] D Faux's cousins by John Lerch <>
- Re: [DNA] D Faux's cousins by Obed W Odom <>
**Re: [DNA] D Faux's cousins by Obed W Odom <>**

- Re: [DNA] D Faux's cousins by Obed W Odom <>