Pictured above is an alien who displays all of the dominant
characteristics of its species. Below is a chart listing various traits
found in this alien race. Use the information in the chart to solve the
genetics problems that follow.
| Trait | Dominant Phenotype | Recessive Phenotype |
| Body color | (P) Purple | (p) Yellow |
| Head adornment | (G) Green horns | (g) Gold antenna |
| Tongue color | (R) Red | (r) Black |
| Fur | (F) Present around neck & waist | (f) Absent - no fur |
| Number of fingers | (H) Four | (h) Seven |
| Shape of feet | (W) Webbed | (w) Clawed |
1. A heterozygous purple male mates with a yellow female. What is the chance this couple will produce a yellow baby? answer
2. A pure red-tongued female mates with a hybrid red-tongued male. What is the chance this couple will produce a baby with a heterozygous genotype? answer
3. Two web-footed aliens mate. The male alien's mother had claws but the female aliens parents were both homozygous. What is the chance the mating couple will produce a baby with claws? answer
4. A female alien with 4 fingers is married to a 7-fingered male. They have ten children. Eight of the children have four fingers but two have seven fingers. What is the mother's genotype? answer
5. A male alien with fur and gold antenna mates with a female alien who lacks fur but has green horns. What is the chance that this couple will produce a furless baby with gold antenna? (Note: the aliens were genetically tested and are heterozygous for all dominant traits) answer
6. A male hybrid for the tongue and body color but pure for four fingers mates with a female who is homozygous purple but displays the recessive phenotype for the tongue color and the number of fingers. What is the chance that this couple will produce a purple baby with a red tongue and seven fingers? answer
7. A yellow female alien with claws mates with a purple,
webbed-footed male. The couple's first child is purple like his dad but
has claws like his mom. What is the genotype of the child? answer
The same couple mates again and this time produces
twins. One of the twins looks just like her dad (purple with webbed feet),
the other twin also has webbed feet like his sister and his dad but is yellow
like his mom. Provide the genotypes of the twins and the genotype of the
father. answer
1. male = Pp female = pp
chance of yellow baby (pp) = 50%
2. male = Rr female = RR
chance of baby with heterozygous genotype (Rr) = 50%
3. male's mother = ww female's
parents = WW
male = Ww
female = WW
chance of baby with claws (ww) = 0%
4. mother = H? father = hh 4-fingered kids = Hh 7-fingered kids = hh
mother's genotype has to be Hh based on the production of the 7-fingered kids
5. male = Ff gg female = ff Gg
chance of furless baby with gold antenna (ff gg) = 4/16 = 1/4 or 25%
6. male = Pp Rr HH female = PP rr hh
chance of purple baby with a red tongue
and seven fingers = 0%
[4/4 chance for
purple baby]
[2/4 chance
for red-tongued baby]
[0/4 chance
for seven-fingered baby] - this one makes the entire combination impossible
7. male = P? W? female = pp ww
purple child with claws = Pp ww [the
kid has to be heterozygous for the body color
'cuz of mom's genotype]
twins:
female (purple & webbed
feet) = Pp Ww
male (yellow & webbed feet)
= pp Ww
father's genotype = PpWw
dad has to be heterozygous for
both traits since his 1st child had claws and the
male twin was yellow -
e.g. the recessive phenotypes were produced