Pedigree Notes SNB pg 109

What does pedigree mean? Pedigree: a diagram that traces one trait through several generations of a family X

Symbols Circle = female Square = male Normal or without trait = unshaded Trait = shaded

Example #1 How many girls? ___ How many boys? ___ momdad son daughter #1 3 2 daughter #2

A horizontal line connecting two shapes represents a cross/marriage. momdad Married couple or couple producing offspring = horizontal line connecting midpoint of circle and square

Example #2 How many crosses/marriages? 2 AB CDE F G

momdad oldestyoungest son daughter #1daughter #2 A vertical line and a bracket connect the parents to their children Children are placed from oldest to youngest.

Symbols If an individual has one recessive allele for a trait, the person is a carrier. This is shown with a half-shaded square or circle. A circle/square that is shaded means the person HAS the trait. A circle/square that is not shaded means the person does not have the trait.

Symbols One offspring Multiple Offspring How do you differentiate between a brother and sister and a husband and wife on a pedigree?

Generations Each generation is (often) labeled with a Roman numeral. Oldest generation at top of pedigree Current generation at bottom

Generations Individuals in each generation may be numbered or named. Siblings are placed in birth order from left to right

Pedigree Part 2 Notes SNB pg 111

AB CDEF How do you show twins?

Other Symbols Death – a single slash is drawn through the symbol. Adopted – brackets are placed around the symbol A B C D

Analysis 1)How many offspring were produced by generation 1? 2)Number of boys? Girls? 3)How many of generation II were married with children? 4)How many deaths are there in this pedigree?

Example #3 How many couples have children? 4 AB CDEF H GH KJL MNO PRQST ?

How do you show traits? Shading RRRr mutation rr **A pedigree chart follows one trait. ( shaded = recessive )

Rr mom RR dad Rr son Rr daughter RrRr R RR Rr RR daughter R = tongue roller r = non-roller

AB CDEF H GH KJL MNO PRQST Practice questions…

What is wrong with this pedigree chart? This offspring cannot receive 2 recessive genes. This offspring cannot receive 2 dominant genes.

What are possible genotypes for individual W? W RrRr R r RRRr rr W could be RR (no shading) or Rr (half-shaded) or rr (all shaded).

Pedigree Worksheet Finish the front in class. Will go on SNB pg 110 after it is graded.

Polydactyl Trait Who did individual #7 generation III inherit the trait from? Who is the first individual with the trait on the pedigree chart?

Polydactyl Trait Based on the pedigree chart, is the trait for multiple digits (fingers and toes) dominant or recessive? How can you tell?

Analysis of a Recessive Trait How many individuals on this pedigree have the trait? How many are carriers?

Analyzing a Trait Sometimes a pedigree is drawn without the carriers shown. Can you tell if the trait is recessive or dominant? Explain. HINT: Dominant Traits NEVER skip a generation

Dominant or Recessive Trait?

Pedigree Charts Show relationships within a family In genetics: Used to show how an inherited trait is passed through a family Example of Trait = Albinism