I have reflected over the comments posted in this thread. It is extremely important to understand that when I say that Y-DNA could influence one's physical appearance:
1) It is a very minor influence that has mostly to do with how a boy turns into a man at puberty. Autosomal DNA is still the most important for overall appearance.
2) Differences in looks between Y-DNA haplogroups should be greater between very different haplogroups (number of different SNPs), and especially if mutations occur in coding genes. Actually there may not be much difference between subclades of a same haplogroup, or even between haplogroups such as I1 and I2, if there is no change in the coding region.
3) If Y-DNA produces visible physical changes at puberty, these will be most obvious between members of a same ethnic group than between ethnic groups. For example, it may be possible to guess which Jewish man belongs to J2, as opposed to R1a, but it may not be possible to use these same clues for other ethnic groups because of the big differences in autosomal DNA that interfere with overall appearance. So there is no way that a Chinese N1c will look anywhere close to a Europe N1c ! I can't believe I have to explain that, but reading the comments I really feel like I have to explain every thing, even the obvious. A Chinese N1c might look a bit different from a Chinese C3 or O3. A Finnish N1c might be distinguishable from a Finnish I1 or R1a. But never will the Finnish N1c look like anything like a Chinese N1c ! And even within a certain ethnic group, the physical differences attributable to Y-DNA may not be discernible by people who aren't used to carefully analyse and compare facial features.
1) It is a very minor influence that has mostly to do with how a boy turns into a man at puberty. Autosomal DNA is still the most important for overall appearance.
2) Differences in looks between Y-DNA haplogroups should be greater between very different haplogroups (number of different SNPs), and especially if mutations occur in coding genes. Actually there may not be much difference between subclades of a same haplogroup, or even between haplogroups such as I1 and I2, if there is no change in the coding region.
3) If Y-DNA produces visible physical changes at puberty, these will be most obvious between members of a same ethnic group than between ethnic groups. For example, it may be possible to guess which Jewish man belongs to J2, as opposed to R1a, but it may not be possible to use these same clues for other ethnic groups because of the big differences in autosomal DNA that interfere with overall appearance. So there is no way that a Chinese N1c will look anywhere close to a Europe N1c ! I can't believe I have to explain that, but reading the comments I really feel like I have to explain every thing, even the obvious. A Chinese N1c might look a bit different from a Chinese C3 or O3. A Finnish N1c might be distinguishable from a Finnish I1 or R1a. But never will the Finnish N1c look like anything like a Chinese N1c ! And even within a certain ethnic group, the physical differences attributable to Y-DNA may not be discernible by people who aren't used to carefully analyse and compare facial features.