Purpose : To give students an example of logic needed in order to examine questions of paternity using knowledge from their genetics unit.
Methods:
1) Students should have previously studied genetics, specifically the concept of heterozygosity and homozygosity before trying this game.
2) This is an example of genotypes determined for a small group of wild monkeys.
Blood was analyzed in order to assess paternity in the group and to make decisions regarding conservation of the group. The numbers given represent the number of base pairs found at each locus (1 and 2), so locus 1 120/120 is the genotype of the individual for that locus and makes him homozygous with an allele 120 and another allele 120. Knowing that each baby gets one allele from mom and the other from dad will allow the class to work through the info.
3) This can be done in two ways – give the students the entire list and have them work alone or in small groups in order to build the family tree and decide who the parents of the babies are. OR cut the papers along the dotted line and pass the sheets to the students so that each student is an individual (ex: Mom 1) and then as a class work out the parentage of the babies. The large group activity leads to some fun competition and reasoning out loud and may work very well for classes.
4) A follow-up exercise would be to have the students build a pedigree of the animals in the population based on the knowledge they now have. Emphasize the lack of knowledge about the rest of the potential dads, as well as no knowledge about how all of the adults are related. This is exactly the problem that conservationists face.

Solutions :
Baby A: Mom1, Dad4
Baby B: Mom1, Dad4
Baby C: Mom2, Dad1
Baby D: Mom2, Dad1
Baby E: Mom3, Dad2
Baby F: Mom3, Dad2
Logic used to solve the problem :
Start by solving for the mom.
Baby A: locus 1 156/156, appears to belong to M1 who is 156/156, while M2 and M3 do not have a 156. To confirm look at second locus for baby 266/274, both alleles match M1 and not M2 and M3, so therefore M1 is baby A’s mom.
Baby B: is almost identical to Baby A, same logic applies. M1 is mom.
Baby C: locus 1: 132/164, could have received 164 from either M2 or M3. Look at the second locus 248/280, 248 could have come from M2. Therefore Baby C belongs to M2 .
Baby D: locus 1 is identical to baby C (see above), locus 2: 236/280, 236 could have come from M2 , and therefore she is mom.
Baby E: locus 1: 164/172, the 164 could have come from M2 or M3, locus 2: 232/256, the 232 could have come only from M3, therefore baby E belongs to M3 .
Baby F: locus1: 164 could have come from M2 or M3, locus 2: same as above for Baby
E, therefore Baby F belongs to M3 .
Now look at the dads. The key is to remember which allele came from mom to help eliminate some of the possibilities.
Baby A: locus 1: 156/156, D4 and D5 both have 156 as an allele making them potential dads, locus 2: 266/274, D5 does not contain either allele which eliminates him, leaving
D4 as the father.
Baby B: locus 1: 156/156, same as above for Baby A, locus 2: 274/274, see above. The dad for Baby B is also D4 .
Baby C: locus1: 132/164, D1 and D2 could have fathered this infant, locus2: 248/280 D2 has neither allele leaving D1 as the father.
Baby D: locus1: same as baby C, locus2: 236/280, again the only possibility is D1 .

Baby E and F are more complicated!
Baby E: locus1: 164/172, could have come from D2, D3, or D5. locus 2: 232/256 could have come from D2, D3 or D7. We can eliminate D5 and D7 because they don’t match at both loci. To decide between D2 and D3 we need to look at the alleles that came from mom. Baby E’s mom is M3 locus 1: 164/172 locus 2: 232/232.
M3
Baby E
164/172 232/232
164/172 232 /256
Baby E must have received 232 from mom (that is all she had to give), therefore 256 had to come from dad, which eliminates D3, leaving D2 as Baby E’s dad.
Baby F: locus 1: 128/164 could have come from D2, D3, or D7. locus 2: 232/256 could have come from D2, D3, or D7. Following the logic from Baby E, dad must contribute
256 to the baby therefore D2 is dad.

Locus 1: 156/156 Locus 2: 266/274
Locus 1: 164/164 Locus 2: 236/248
Locus 1: 164/172 Locus 2: 232/232
Locus 1: 156/156 Locus 2: 266/274
Locus 1: 156/156 Locus 2: 274/274
Locus 1: 132/164 Locus 2: 248/280

Locus 1: 132/164 Locus 2: 236/280
Locus 1: 164/172 Locus 2: 232/256
Locus 1: 128/164 Locus 2: 232/256
Locus 1: 132/132 Locus 2: 280/280
Locus 1: 128/164 Locus 2: 256/256
Locus 1: 128/172 Locus 2: 200/232

Locus 1: 156/156 Locus 2: 274/274
Locus 1: 156/174 Locus 2: 200/200
Locus 1: 120/150 Locus 2: 286/300
Locus 1: 128/128 Locus 2: 232/232
Locus 1: 120/120 Locus 2: 220/224