Inheritance Pattern of Earlobe Attachment amongst Nigerians

Ordu, K. S.; Didia, BC; Egbunefu, N.

doi:10.15580/gjhpa.2014.1.012214054

Cited by 17 publications

(19 citation statements)

References 7 publications

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“…Hence, longer big toe might have expressed some level of dominance over shorter big toe, but this is not a clear indication of the dominance of the longer big toe. Although various researchers have expressed doubts that Morton's toe, like several other traits such as ear lobe attachment[41415] and nose shape,[5] which is believed to be transmitted in a Mendelian fashion, is rather based on more complex genetic models. [813] Kaplan[10] claimed that the relative length of the hallux and second toe is simply inherited with long hallux being recessive; nevertheless, this was not the case in this study; as the Mendelian Chi-square model show more conformance of dominance for the longer big toe.…”

Section: Discussionmentioning

confidence: 99%

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Morton's toe: Prevalence and inheritance pattern among Nigerians

Aigbogun

Alabi

Didia

et al. 2019

Int J App Basic Med Res

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Background: Anatomical variations have been genetically linked and the difference in the length of the big toe relative to the second toe (Morton's toe) is not an exception; however, its prevalence and inheritance pattern has been a scientific debate. Therefore, this study investigated the prevalence and inheritance pattern of Morton's toe among Nigerians in Rivers State. Materials and Methods: A total of 101 families comprising of 101 parents (fathers and mothers) and 135 offspring were conveniently sampled for this study. The observed big toe pattern was described as “L BT ” and “S BT ” representing big toe longer than the second toe and big toe shorter or equal to the second toe, respectively. The offspring trait was tabulated alongside the parental combination patterns (i.e., when both parents had L BT , both parents S BT and a combination of L BT and S BT ). XLSTAT 2012 (version 4.2.2) Chi-square analysis tested the association between sex and Morton's toe. Mendelian Chi-square gene distribution model evaluated the conformance to simple dominance-recessive pattern, while the Hardy–Weinberg (H-W) equation for allele frequency compared the parental allele frequency to that of the offspring. Results: L BT (218; 64.7%) was more in the studied population than S BT (119; 35.3%); with males (63; 18.7%) having slightly higher proportion of SBT (Morton's toe) than females (56; 16.6%), which was without sexual preference (χ 2 = 0.141, P > 0.932). The test of offspring gene distribution in conformance to Mendelian simple dominant-recessive monohybrid cross had rather weak result. The H-W equation showed a deviation of offspring allele distribution (1:3:2.5 [2:6:5]) from the parents (1:3:2). Conclusion: Morton's toe could be said to be genetically linked, however, its inheritance pattern does not conform to the simple dominant-recessive model, but a more complex pattern. It should be noted that the large frequency of a trait in a population does not make it dominant.

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Section: Discussionmentioning

confidence: 99%

“…However, humans have numerous traits, but some traits are more frequently seen in population such as free-hanging earlobes, ability to roll their tongue, straight hairline, and right-handedness. [45] These traits are often expressed in different patterns, which are applicable in clinical and forensic investigations. [16]…”

Section: Introductionmentioning

confidence: 99%

Morton's toe: Prevalence and inheritance pattern among Nigerians

Aigbogun

Alabi

Didia

et al. 2019

Int J App Basic Med Res

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“…Earlobe attachment (MIM: 128900 ) is often presented as an example of a readily observable Mendelian phenotype in educational materials 1 and continues to be studied as a Mendelian phenotype in the contemporary primary literature (for example, see Ordu et al. 2 ). Yet, as early as 1937, Wiener 3 pointed out that earlobe attachment is likely to be a polygenic trait exhibiting a continuous phenotypic distribution.…”

Section: Introductionmentioning

confidence: 99%

Multiethnic GWAS Reveals Polygenic Architecture of Earlobe Attachment

Shaffer¹,

Li²,

Lee³

et al. 2017

The American Journal of Human Genetics

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The genetic basis of earlobe attachment has been a matter of debate since the early 20th century, such that geneticists argue both for and against polygenic inheritance. Recent genetic studies have identified a few loci associated with the trait, but large-scale analyses are still lacking. Here, we performed a genome-wide association study of lobe attachment in a multiethnic sample of 74,660 individuals from four cohorts (three with the trait scored by an expert rater and one with the trait self-reported). Meta-analysis of the three expert-rater-scored cohorts revealed six associated loci harboring numerous candidate genes, including EDAR, SP5, MRPS22, ADGRG6 (GPR126), KIAA1217, and PAX9. The large self-reported 23andMe cohort recapitulated each of these six loci. Moreover, meta-analysis across all four cohorts revealed a total of 49 significant (p < 5 × 10−8) loci. Annotation and enrichment analyses of these 49 loci showed strong evidence of genes involved in ear development and syndromes with auricular phenotypes. RNA sequencing data from both human fetal ear and mouse second branchial arch tissue confirmed that genes located among associated loci showed evidence of expression. These results provide strong evidence for the polygenic nature of earlobe attachment and offer insights into the biological basis of normal and abnormal ear development.

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“…Studies have shown that no two individuals are exactly the same; differences occurring in humans could be as a result of selection, migration and mode of inheritance (Bhasin et al, 1992). Inheritance is the mode of transmitting biological traits from parents to offspring through gene (Ordu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

A study on tongue rolling, tongue folding and cerumen type in a Nigeria population

Abimbola¹

2019

Anat. J. Afr.

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This study investigated Variation in cerumen type, tongue rolling and tongue folding abilities of the Esan people of Southern Nigeria. This cross-sectional survey investigated 400 volunteered adult subjects (176 males and 224 females) between the ages of 18 and 60 whose parents and grandparents were of Esan ethnicity. The tongue and ear wax type were observed and examined physically thus classifying subjects into rollers/none-rollers, folders/none-folders and dry or wet cerumen type. Results indicates that tongue rollers (72.9%) were more than non-rollers (27.3%), in the same vein, tongue folders (68.3%) were also more than non-folders (31.7%) in the studied population. A larger percentage of the population also had wet ear wax (65%) while (35%) had dry ear wax. The chisquared analysis of variance showed that there is a significant difference (P<0.05) between those who can roll their tongue and those who cannot, those that could fold their tongue and those who cannot as well as between those with wet ear wax and dry ear wax. This study therefore provides data on the distribution of tongue rollers, tongue folders as well as variability in cerumen type. This data can be of importance to the anthropologist and forensic investigators.Keywords: Variation, Genetics, Inheritance, tongue rolling, tongue folding, cerumen type

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Inheritance Pattern of Earlobe Attachment amongst Nigerians

Cited by 17 publications

References 7 publications

Morton's toe: Prevalence and inheritance pattern among Nigerians

Morton's toe: Prevalence and inheritance pattern among Nigerians

Multiethnic GWAS Reveals Polygenic Architecture of Earlobe Attachment

A study on tongue rolling, tongue folding and cerumen type in a Nigeria population

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