Naturally Curly Hair
There are two versions of the hair type gene, curly (C) and straight (s). Hair type is an example of incomplete dominance.
If you have one of each version of the gene, you get a mix of the two or wavy hair. So for hair type, CC gives curly, Cs gives wavy and ss gives straight hair.
Color Blindness
Traits that are determined by alleles carried on the X chromosome are referred to as X-linked. X-linked alleles require a specific notation: Xc (recessive allele) or X+ (Dominant allele).
Females will have two X-linked alleles (because females are XX), whereas males will only have one X-linked allele (because males are XY).
One example of an X-linked trait is red-green colorblindness.
Females that are X+X+ or X+Xc have normal color vision,
Females that have XcXc are colorblind.
Males that are X+Y have normal color vision
XcY males are colorblind.
(Xc) -recessive allele that causes colorblindness
(X+)- the normal dominant allele.
Hand Clasping
Most people place their left thumb on top of their right and this happens to be the dominant phenotype.
Right thumb on top of left thumb is recessive.
References
http://knowgenetics.org/dominant-inheritance/
http://thehappyscientist.com/science-experiment/ear-genes
http://genetics.thetech.org/ask/ask125
https://ghr.nlm.nih.gov/primer/traits/handedness
http://www.brighthub.com/science/genetics/articles/13998.aspx
https://www.google.com/search?q=how+to+determine+pattern+of+inheritance+for+cleft+chin&biw=1920&bih=953&source=lnms&tbm=isch&sa=X&ved=0ahUKEwii5uio7cXSAhWG1IMKHSd9B1oQ_AUICCgB#imgrc=9odPT3uTRB2HRM:
http://genetics.thetech.org/ask/ask45
http://www.scienceprofonline.com/genetics/ten-human-genetic-traits-simple-inheritance-2.html
http://knowgenetics.org/x-linked-inheritance/
http://learn.genetics.utah.edu/content/basics/observable/
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