A breeder wants to produce freshwater fish with an inherited ability to survive when the dissolved oxygen concentration is low.
Four pairs of fish produced offspring. Equal numbers of offspring from each pair were raised under the same conditions and then exposed to the same low dissolved oxygen concentration.
| parent pair | offspring surviving after 6 hours (%) |
|---|---|
| P | 38 |
| Q | 64 |
| R | 49 |
| S | 57 |
Give the parent pair whose offspring should be selected for breeding.
Explain how the breeder should continue the selective breeding programme so that survival at low dissolved oxygen concentrations becomes more common in the population.
100 exam-style questions on Edexcel GCSE Biology 4.3 Selective breeding and genetic modification, covering 4.3.1 Selective breeding and its impact, 4.3.2 Tissue culture, 4.3.3 Genetic engineering overview, 4.3.4 Main stages of genetic engineering, 4.3.5 Advantages and disadvantages of GM organisms, 4.3.6 Agricultural solutions for a growing population, and 4.3.7 Evaluating genetic engineering and breeding. Each one has a worked solution and a mark scheme showing where the marks go.