Family trees for a single trait. Genetics. 4º ESO. IES Antonio Gala

Our students have to choose a single trait that is either recessive (homozygous) or dominant (homozygous or heterozygous) in their families.

You can pick a trait out of this list:

- Attached earlobes 

- Rolling tongue 

- Straight or curved thumb 

- Dimples when smiling 

- Freckles on your face 

- Widow´s peak versus straight hairline 

- Which thumb is on top when you interlace your fingers 

- Handedness (left or right) 

- Second longer toe  

It will look very alike to this example.

Source of information: http://www.wissensdrang.com/wisbr2.htm


Family trees or charts can be very helpful to trace diseases in families within generations, specially those where marriages happen between cousins. 
Haemophilia is a sex-linked trait to chromosome X.

Source of information: http://evolution.berkeley.edu/evolibrary/article/similarity_hs_04


Hereby there is a presentation for a better understanding


PEDIGREE CHARTS A family history of a genetic condition or trait.

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