The David McWilliams genetic conundrum

strassenwolf

I was reading Mr McWilliams' column in today's Business Post - as usual, in my opinion, interesting stuff - and I came across the following comment, which jarred a little bit. It's obviously not a big thing, and may well have been a slip of the pen, but I'd be interested to get the views of the board.

David McWilliams wrote:

Some 20,000 feet below lie the Westman Islands, a great volcanic archipelago named after the Westmen - the Irish -who were taken here as slaves by the Vikings in the 10th century. This story explains why 30 per cent of Icelanders have Irish, not Norse genes. What’s more, considerably more Icelandic women than men have Irish genes, because the Vikings did what it said on the tin: they raped and pillaged, taking slave concubines home with them.

http://www.thepost.ie/post/pages/p/story.aspx-qqqt=DAVID+McWilliams-qqqs=commentandanalysis-qqqid=40624-qqqx=1.asp

I'm not quite sure what constitutes an Irish gene, but that's not really the point here. Let's assume there are such things.

There have been several generations since these slave concubines were relocated.

Assuming that these women were no different to other women around the world, they should - collectively - have produced approximately an equal number of sons as they did daughters. And those offspring would -collectively - have continued to do the same.

Given a 50:50 ratio of expressive genes from both the father and the mother in any union which produces offspring, one would imagine that these "Irish genes" should be approximately evenly divided between the sexes.

I hope the contributors on this board get what I'm trying to say. (I'm afraid this is my first post on the Biology and Medicine board).

My feeling is that unless these "Irish genes" - whatever they might be - are located on the sex chromosomes, a situation referred to by Mr McWilliams cannot be possible.

Am I correct?

hardtrainer

When looking at genetics on this level (i.e. population genetics) you need to find a way to look at the variability that exists between individuals both within a particular group and between groups (i.e. within Iceland and between Iceland and Ireland). This is done using SNPs (single nucleotide polymorphisms....a change in a single DNA base from say a T to an G and so on). As the genome changes over multiple generations (e.g. mutations or rearrangements) individuals with comparatively recent common ancestors are more likely to have particular SNPs or groups of SNPs in a particular location than if you compared the same DNA region between two individuals who do not share a recent common ancestor. So when he speaks of Irish genes, he means DNA sequences which are very common among the Irish population, but which are much less common, or even absent in other populations. These differences do not necessarily imply any differences in gene functions (should the differences occur within coding sequence of a gene) but thats also possible.

With respect to the sex disparity, I don't know really. I can't think of any reason to suggest that there should be more females carrying these 'Irish genes' than males, but it might have less to do with genetics and more to do with sperm competition and the frequency of sex with the Irish slaves.

darjeeling

This thread somehow got duplicated at the outset. Could it be merged with its twin (here)?

sillymoo

I have yet to meet an Icelander who has red hair and freckles.

DrIndy

sillymoo wrote: »

I have yet to meet an Icelander who has red hair and freckles.

I have - they look freaky. Lot of red beards over there

strassenwolf

darjeeling wrote:

This thread somehow got duplicated at the outset. Could it be merged with its twin (here)?

Sorry about the double post. An error which I wasn't sure how to rectify.:o

In case the threads are not merged, thanks, darjeeling, for your replies to the original question.

marco_polo

strassenwolf wrote: »

I was reading Mr McWilliams' column in today's Business Post - as usual, in my opinion, interesting stuff - and I came across the following comment, which jarred a little bit. It's obviously not a big thing, and may well have been a slip of the pen, but I'd be interested to get the views of the board.



http://www.thepost.ie/post/pages/p/story.aspx-qqqt=DAVID+McWilliams-qqqs=commentandanalysis-qqqid=40624-qqqx=1.asp

I'm not quite sure what constitutes an Irish gene, but that's not really the point here. Let's assume there are such things.

There have been several generations since these slave concubines were relocated.

Assuming that these women were no different to other women around the world, they should - collectively - have produced approximately an equal number of sons as they did daughters. And those offspring would -collectively - have continued to do the same.

Given a 50:50 ratio of expressive genes from both the father and the mother in any union which produces offspring, one would imagine that these "Irish genes" should be approximately evenly divided between the sexes.

I hope the contributors on this board get what I'm trying to say. (I'm afraid this is my first post on the Biology and Medicine board).

My feeling is that unless these "Irish genes" - whatever they might be - are located on the sex chromosomes, a situation referred to by Mr McWilliams cannot be possible.

Am I correct?

He is referring to Mitochondrial Dna studies, which is inherited solely from the maternal side.

EDIT: Just read twin thread, this was long answered, don't mind me:)