The adult height of children is not in all cases directly correlated to the height of their parents. It is estimated that genetic factors affect 60-80% of the final adult height. Conversely, about 20-40% is determined by environmental factors (dietary, disease exposure, etc.). Studies with 8,798 pairs of adult Finnish twins, published in the Behavior Genetics Journal, have shown that genetic factors can determine the final height to 78% on adult men and 75% on adult women. In this post, we’ll cover the relationship between height and genetics.
Height and Genes
An individual’s height is strongly determined by the inherited DNA sequence variants. However, it’s only partially understood in which genes these DNA sequences are located in and what impact they have. The human body consists of about 60 trillion cells, and inside the nucleus of each cell are 46 chromosomes. 23 are inherited each from the mother’s egg and the father’s sperm. These chromosomes are engraved with genes that represent our appearance, constitution, character, and responsiveness to disease.
700 variants of genes that are affecting the height have been identified so far by Genome-wide SNP (Single Nucleotide Polymorphism) analysis. In this case, SNP refers to a phenomenon that occurs because one base of a specific region of the DNA strand that holds the gene is different. Appearance and personality are different because of the difference of one base out of 3 billion pairs of bases. Researchers involved in the International Genetic Investigation of Anthropometric Traits (GIANT) Consortium have identified 83 new, relatively uncommon DNA changes that can have dramatic effects on height, affecting a person’s stature by more than 2 centimeters (about 0.8 inches). Some rare gene mutations have a dramatic effect on height and body functions such as a malfunctioning bone formation, symptoms of small hands, feet or minor facial deformities.
Genetic Impact of Age, Gender, and Region
Genetic influences may vary according to age, gender or even region. First, let’s look at the differences in genetic effects of age. According to an international study of over 12,000 twin pairs in four countries (Canada, Sweden, Denmark, Australia), aged 0 through 19, heritability for body weight, height, and BMI was low at birth but increased over time. For body height, the effect of the common environment during early childhood remained significant for a longer period (up through 12 years of age). In other words, as they grow, they are increasingly affected by genetics.
In another study among Finnish twins, a difference in the genetic influence of gender was found. According to the study results, male height is more genetically affected than the height of females. Subsequently, this means that women are more affected by environmental factors than men.
In an international study with 45 twin cohorts from 20 different countries, the genetic impact between geographic-cultural regions (Europe, North-America, Australia, and East-Asia) was observed. The findings showed that the genetic variance was greatest in North America and Australia, and lowest in East-Asia.
- Genetic and environmental contributions to the association between body height and educational attainment: a study of adult Finnish twins (Silventoinen K, Kaprio J, Lahelma E)
- Is height determined by genetics?, Genetics Home Reference
- Epigenetic heredity of human height (Pasquale Simeone, Saverio Alberti)
- Rare and low-frequency coding variants alter human adult height, Nature
- Hundreds of variants clustered in genomic loci and biological pathways affect human height, GIANT Consortium
- Genetic and Environmental Contributions to Weight, Height, and BMI from Birth to 19 Years of Age: An International Study of Over 12,000 Twin Pairs
- Relative Effect of Genetic and Environmental Factors on Body Height: Differences Across Birth Cohorts Among Finnish Men and Women (Karri Silventoinen, MSc, Jaakko Kaprio, MD, Eero Lahelma, PhD, and Markku Koskenvuo, MD)
- Genetic and environmental influences on height from infancy to early adulthood: An individual-based pooled analysis of 45 twin cohorts, SCIENTIFIC REPORTS