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I have matrices of genetic distances for x number of individuals within a population and their corresponding point coordinates -one genetic distance matrix per point coordinates.

I was imagining using the Mantel test, i.e. evaluate the significance of correlations between genetic and geographic distances. However, what I did not think of was that these two types of matrices will have different dimensions (e.g. a genetic matrix of 15 ind = 15x15, sampled at three locations = 3x3), hence the Mantel test will not work. I am now looking into Moran's I, testing for spatial autocorrelation, but it will not work with my data as it currently is. I would need one measure of variation per point coordinates. Would it be legit (never seen anyone do this) to derive a measure of variation (e.g. var, sd, cv) from a single distance matrix? Since the matrix is normalized, ranging from 0-1, maybe var or sd would work?

I am kinda new to analyzing spatial data, so I would appreciate any pointers or alternative tests I might be able to do.

Thanks,

jO.
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  • I am sure that you find useful information in this question (it also contain links to useful articles) http://stats.stackexchange.com/questions/72685/why-is-mantels-test-preferred-over-morans-i – Ladislav Naďo Jan 31 '14 at 11:36
  • @LadislavNado Cheers for commenting. Yeah, I have read through this already. It's a good one. – jO. Jan 31 '14 at 11:57
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    Hi. I am sorry but with just 3 locations you can forget about spatial statistics - you won't be able to calculate Moran's I or Mantel properly (believe me such approach will be hard to defend in peer-review), and i think you should do some simple "ANOVA-like" analysis instead (try to explain variability within and between groups). – Ladislav Naďo Jan 31 '14 at 14:43
  • @LadislavNado Ah, yeah you're probably right. Cheers – jO. Jan 31 '14 at 15:03
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    ...Im thinking of adonis {vegan} analysis which is a non-parametric version of MANOVA – jO. Jan 31 '14 at 15:30
  • I will look on it {adonis} - (may be it will solve not only your problem be my problem also). Thanks you for it! I contact you later. – Ladislav Naďo Jan 31 '14 at 16:20
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    Now, after reading and trying to understand various tests, I think Betadisper {vegan} would work for me. It tests if groups differ in their variance compared to adonis which tests the difference in centroid position. It is basically Levene's test for homogeneity of variances/homoscedasticity which assesses the equality of variances for a variable (genetic distance) calculated for two or more groups (locations). – jO. Jan 31 '14 at 17:31

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