Human Inheritance-text pp i) Dominance and recessive- ii) Co dominance – Human Blood groups Other Types of inheritance iii) Single Gene-Multiple alleles (Human Eye Colour) iv) Using Pedigrees v) Gender determination vi) Sex Linkage – X Linked

i) Recessive trait

Dwarfism - dominant

Dominant does not mean you will see lots of examples automatically in populations of individuals. It might be that it is a rare dominant form of a gene (allele) eg; dwarfism. The gene is said to have a low frequency in the human population Similarly recessive traits can be quite common in populations where the trait has a high frequency eg blue eyes in northern European populations eg; Danish, Swedish etc.

Dominant

Curved little finger - dominant

Observable Genetic Traits Characteristicdominant traitrecessive trait EarlobesFree ear lobesAttached ear lobes ForelockWhite forelockNo white forelock Curve of thumbStraight thumbCurved thumb Dimples No dimples PinkyBent pinkyStraight pinky Mid-digit hair No mid-digit hair Tongue rollingAble to rollNot able to roll Writing Handrightleft Crossing legsLeft Leg upRight leg up Second toe Lengthlongershorter

ii)Co dominance – Human Blood groups

ii)Co dominance – Human Blood groups Both Alleles are expressed in the phenotype

iii)Single Gene Inheritance-Multiple Alleles e.g Human Eye Colour

Discontinuous(one gene) VS Continuous(many genes) Characteristics

iv)Using Pedigrees

Create Your own Pedigree for ear lobe attachment

v)Gender Determination

vi)Sex Linked Diseases eg Colour Blindness(can you see the number)

ting/colour/colourblind.html

Comparison of X and Y chromosomes

X and Y chromosome Comparison

Colour Blindness(sex linked) Parents=Carrier female x Normal sited male X X X XY

Now do Everyone read pp If finding work hard complete Q 1-7 If finding easy -Completed Q13,14,15,16,17,24