February 18, 2009

19th century trumps 21st (for predicting height)

What this study has found is that predicting a person's height from that of his parents is much more accurate than predicting it from all discovered height-related genetic loci combined.

Of course, we need to pursue genomics, since that is the only way in which we will eventually learn how height is inherited, and which biological factors affect growth. But, for practical purposes, and for the foreseeable future, I doubt that we'll get more information about a baby's prospects by looking at its genes, than by looking at its family.

For some background on the underwhelming results of genomics see In search of the hidden heritability.

European Journal of Human Genetics advance online publication 18 February 2009; doi: 10.1038/ejhg.2009.5

Predicting human height by Victorian and genomic methods

Yurii S Aulchenko et al.


In the Victorian era, Sir Francis Galton showed that |[lsquo]|when dealing with the transmission of stature from parents to children, the average height of the two parents, |[hellip]| is all we need care to know about them|[rsquo]| (1886). One hundred and twenty-two years after Galton's work was published, 54 loci showing strong statistical evidence for association to human height were described, providing us with potential genomic means of human height prediction. In a population-based study of 5748 people, we find that a 54-loci genomic profile explained 4-6% of the sex- and age-adjusted height variance, and had limited ability to discriminate tall|[sol]|short people, as characterized by the area under the receiver-operating characteristic curve (AUC). In a family-based study of 550 people, with both parents having height measurements, we find that the Galtonian mid-parental prediction method explained 40% of the sex- and age-adjusted height variance, and showed high discriminative accuracy. We have also explored how much variance a genomic profile should explain to reach certain AUC values. For highly heritable traits such as height, we conclude that in applications in which parental phenotypic information is available (eg, medicine), the Victorian Galton's method will long stay unsurpassed, in terms of both discriminative accuracy and costs. For less heritable traits, and in situations in which parental information is not available (eg, forensics), genomic methods may provide an alternative, given that the variants determining an essential proportion of the trait's variation can be identified.


1 comment:

Maju said...

the Galtonian mid-parental prediction method explained 40% of the sex- and age-adjusted height variance,

Ok. But still it's ONLY 40%. There's a 60% (more than half) unpredictable and that's A LOT.