Dermatoglyphics connotesfriction ridges on the skin, visibleon fingers, toes, and palms of individuals. These epidermal ridges, especially finger prints have proven to be viable physical features in criminology, medical diagnosis genetic studies. Handedness; observed as an individual’s preferred use a particular hand over other, for daily activities has been attributed uneven distribution fine ...

According to the Geschwind-Galaburda theory of cerebral lateralization, high intrauterine testosterone levels delay left brain hemisphere maturation and thus promote left-handedness. Human circulating testosterone levels are higher in the male fetus and also vary with length of photoperiod. Therefore, a higher prevalence of left-handedness, coupled with seasonal anisotropy (i.e., a non-uniform ...

The percentage (10-13%) of left handedness in human has apparently not changed since the Neolithic. Left handedness is heritable and appears to be repeatedly associated with some reduced fitness components; the persistence of left handedness implies that left handers have a fitness advantage in some situations. We propose that left handers have a frequency-dependent advantage in fights and for ...

The handedness of seventy-five persons without evidence of neurological disease, was assessed with a standardised test. An analysis of the CT scans of the same persons was performed to determine (1) presence and lateralisation of frontal and occipital "petalia," (2) width of frontal and occipital lobes of each hemisphere, (3) direction of straight sinus deviation. Results suggest that handednes...

Developmental theories of the biological basis of sexual orientation suggest that sexually differentiated psychological and behavioural traits should be linked with sexual orientation. Subgroups of gay men delineated by anal sex roles differ according to at least one such trait: gender expression. The present study assessed the hypothesis that handedness, a biologically determined sexually diff...

Pregnancy- and birth-related factors may have an effect on handedness. Compared with singletons, twins have a lower birth weight, shorter gestational age, and are at higher risk for birth complications. We tested whether the prevalence of left-handedness is higher among twins than singletons, and if so, whether that difference is fully explained by pregnancy and birth-related differences betwee...

Non-shared environmental variance (NSEV) accounts for 76% of in genetic modelling handedness. However, it is very misleading to suggest that NSEV, “highlights the importance non-genetic factors ontogenesis hemispheric asymmetries”. NSEV poorly named, calculated only by subtraction, and provides no direct evidence effects sense external environment. Miller suggested would be better named as “res...

It is frequently stated that right-handedness reflects hemispheric dominance for language. Indeed, most right-handers process phonological aspects of language with the left hemisphere (and other aspects with the right hemisphere). However, given the overwhelming majority of right-handers and of individuals showing left-hemisphere language dominance, there is a high probability to be right-hande...

An association between APOE genotype and left-handedness has been previously reported. We examined whether such association exists in a population sample of 4438 unrelated Caucasian adults aged 45-69 years (2022 males and 2416 females). Left-handedness was based on self-reported left-hand dominance for writing (prevalence 4.9%) and on consistently higher left-hand grip strength in two repeated ...

Functional neuroimaging studies of handedness have traditionally focused on exploring regionally activated discrepancies, yet little is known regarding the effect of handedness on functional connections of brain regions. Here, we reported the relationship between cerebellar functional connectivity patterns and handedness by low-frequency blood oxygenation level-dependent fluctuations. Compared ...