The X chromosome has always fascinated me. Whether it is trying to track down the family mild blue/green color blindness or just observing X inheritance patterns in my family and others.
The old farm house at Fatland farm, Halsnøy Island, June 2015
This morning I woke up all excited because I realized that a large piece of my X chromosome comes from my Norwegian 4th grandmother Metta Olsdatter Ve (Fatland) born 1729 on farm Fatland, likely in the house pictured here. She died in 1805 on farm Ve (or Wee) so made it into the 1801 census.
So how did I figure this X inheritance out? My Dad and I share 33.5 cMs of the X chromosome with my fourth cousin once removed Maria and her mother (so it is phased). They descend from a different wife of our common ancestor Aamund Bjørnsen Tvetden. So these 3326 SNPs of X located from 68M to 113M must come from him and therefore from his mother Metta.
No I did not share this insight with my husband when he brought me my morning coffee. I know better than to make his eyes glaze over … only other genetic genealogy aficionados would appreciate this, so I am sharing it here instead.
By the way I am still collecting X statistics, so click here for more on that and please contribute yours
Several of the Ve farms, Etne, Hordaland , June 2015
I’m very excited for you. What a great discovery.
How do I access gedmatch so I can upload my DNA from Ancestry.com to compare the two
Helen –
Go to GEDmatch.com and set up a user and password. Details are in this post of mine including links to step by steps: http://blog.kittycooper.com/2015/09/please-upload-your-ancestry-raw-data-to-a-site-with-a-chromosome-browser/
I am wondering whether this form of color blindness follows what is the case for the more common X-linked red/green color blindness, in that although females who only have one X with this are classed as carriers, they do to some extent show an effect due to the inactivation of one of the X’s which occurs in females. So even though they do not exhibit the full effect, they do have a testable amount of impairment, due to having a mosaic with one X functioning in some regions and the other X functioning in other regions. Have you any evidence for this in your family?
Vernon – No evidence of it showing up in any women in our family. Tritanomaly is supposed to be carried on chromosome 7 but the version my family has is clearly on the X since no women have any form of it.
But then not all the woman have taken the test. I will ask them all to do so. Interesting idea.
More about my family’s version is here: http://kittymunson.com/index.php?page=colorblindness
My wife has French Canadian ancestry and that appears to be the source of red and green color blindness of her father and his brother, and the yellow-green color blindness of my wife and her father’s mother. Only very obvious with the females with a few shades of pale yellow green colors they do not see at all or some greens they see as a disgusting shade of brown. My wife passed a simple optometrists color blindness test with no problems. Our daughters do not have any apparent color blindness, but one grandson does. Genetics can be fascinating.
We are EXCITED for you, even if dear husband does not (-: