Problem A: Shipwreck Founder Effect Genetics
In the year 1782, a small passenger schooner (the HMS Leaky) was blown off course, crashing into the rocks of a then-uncharted mid-Atlantic island. The 30 survivors built shelter and found plentiful food on the island. Within a year, it was clear that there was little chance of rescue and no means of leaving. Soon, the warm tropical nights led couples to succumb to the romantic tendencies that moonlight walks on the beach can induce. Before long, babies were born, and the ânewâ civilization of the island now known as Gilligania was off to the races.
A genetic analysis of the remains of those original islanders showed the following ABO blood type phenotypes:
Blood Type Number of People A* 9 B** 7 AB 4 O 10
*Four heterozygotes (iA iO) and five homozygotes for iA
** Five heterozygotes (iB iO) and two homozygotes for iB
Keep in mind that the blood type alleles iA and iB are codominant over each other, and that the iO allele is recessive to both iA and iB. If you need to do so, review the genetics of this system in Campbellâs Biology. Based on this information, please answer the following questions (show your work):
1. What were the frequencies of the three alleles in the original survivor population on the island?
2. Determine the genetic structure (allele and genotype/phenotype frequencies) for this gene system in the island population in 1932, when the island was ârediscoveredâ by cartographers. The population at that time had grown to 185 people.
THis was all the information we were given
Problem A: Shipwreck Founder Effect Genetics
In the year 1782, a small passenger schooner (the HMS Leaky) was blown off course, crashing into the rocks of a then-uncharted mid-Atlantic island. The 30 survivors built shelter and found plentiful food on the island. Within a year, it was clear that there was little chance of rescue and no means of leaving. Soon, the warm tropical nights led couples to succumb to the romantic tendencies that moonlight walks on the beach can induce. Before long, babies were born, and the ânewâ civilization of the island now known as Gilligania was off to the races.
A genetic analysis of the remains of those original islanders showed the following ABO blood type phenotypes:
| Blood Type | Number of People |
| A* | 9 |
| B** | 7 |
| AB | 4 |
| O | 10 |
*Four heterozygotes (iA iO) and five homozygotes for iA
** Five heterozygotes (iB iO) and two homozygotes for iB
Keep in mind that the blood type alleles iA and iB are codominant over each other, and that the iO allele is recessive to both iA and iB. If you need to do so, review the genetics of this system in Campbellâs Biology. Based on this information, please answer the following questions (show your work):
1. What were the frequencies of the three alleles in the original survivor population on the island?
2. Determine the genetic structure (allele and genotype/phenotype frequencies) for this gene system in the island population in 1932, when the island was ârediscoveredâ by cartographers. The population at that time had grown to 185 people.
THis was all the information we were given
