Inheritance pattern and association studies of some human morphogenetic traits among Nigerian undergraduate students

Morphogenetic traits are observable characters inherited by individuals from their parents in autosomal dominant or recessive manner and expressed differently among populations. The differences in inheritance and expression of these traits usually form the basis of diversity and variation among populations. This study was carried out to ascertain the distribution, inheritance pattern and association of morphogenetic traits among students of the University of Lagos, Nigeria. Ten morphogenetic traits which includes, widow's peak, hitchhiker's thumb, cleft chin, tongue rolling, earlobe attachment, dimpled cheeks, bent little finger, ability to taste phenylthiocarbamide(PTC), mid-phalangeal hair and polydactyly were assessed by observations among 1000 randomly selected undergraduate students of the University. Association studies between traits were carried out using chi-square test of independence with a threshold of 5% level of significance. The study revealed the distributions of the traits as follows: widow's peak present in 36.8%; double jointed hitchhiker's thumb, 46.5%;cleft chin, 19.9%; tongue rollers, 63.9%; free earlobe attachment, 74.6%; dimpled cheeks,22.0%; bent little finger, 36.7%; ability to taste PTC, 42.9%; presence of midphalangeal hair, 35.35% and polydactyly was found in 6.8% of the participants. Association evaluation showed no significant association between all the morphogenetic traits and gender except for dimpled cheeks (chi(2) = 5.26, p = 0.022). Ability to taste PTC was found to be associated with tongue rolling (chi(2) = 4.46, p = 0.035); widow's peak was associated with cleft chin (chi(2) = 11.63, p< 0.01) and dimpled cheeks (chi(2) = 5.67, p< 0.05). Dimpled cheek was significantly associated with cleft chin (chi(2) = 31.22, p< 0.01). Also, bent little finger was found to be associated with mid-phalangeal hair (chi(2) = 7.13, p< 0.01), polydactyly (chi(2) = 5.67, p< 0.05) and hitchhiker's thumb (chi(2) = 19.24, p< 0.01). More recessive type of traits evaluated were observed among sampled participants, not typed to ethnicity or group. Results obtained in this study are suitable for medicolegal and anthropological studies. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.