In humans, are there phenotypic markers that prove parenthood? For example, if mother and father have <trait characteristic> (let's say, specific ear lobe form), then any child will have <trait characteristic>. If the child does not exhibit that characteristic, than either father or mother or both are only alleged, not actual.

  • $\begingroup$ Interesting question. Eye and hair colour (two "obvious" ones), to my knowledge, can be different from either parent due to the dominant/recessive nature of alleles. I would be interested to know of any "true" <trait characteristic>, as you put it $\endgroup$ – Luke Mar 19 '15 at 14:12
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    $\begingroup$ I've previously heard claims that a cleft chin is such a trait, but this seems to be a myth: udel.edu/~mcdonald/mythcleftchin.html. The trait supposedly has a strong heritable component though. Blood type could sometimes be a strong indication of parenthood (e.g. an O father should normally not produce AB offspring), but not always. $\endgroup$ – fileunderwater Mar 19 '15 at 15:23
  • $\begingroup$ Not that I know of. $\endgroup$ – cagliari2005 Mar 22 '15 at 20:28

No. To determine the genetic relationship (if any) between two individuals requires molecular evidence based on genetic markers in their somatic DNA. Using phenotypes could be misleading because a genetic marker (an allele) can have variable penetrance (the percentage of carriers who actually have the phenotype) and variable expressivity (the severity or degree of the phenotype). Some of this variability can come from gene-environment interactions, and some could come from epigenetic effects (ie non-heritable).


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