In genetic investigations on the fruit fly Drosophila melanogaster, a researcher crosses a fly homozygous for normal-length wings (Fly 1) with a fly that has vestigial (very short) wings (Fly 2). Normal wing length is dominant over vestigial wings.
Use the following symbols for the alleles:
Fly 1 (genotype WWWWWW) is crossed with Fly 2. All offspring in the first filial (F1\text{F}_1F1) generation have normal-length wings.
Two of these F1\text{F}_1F1 offspring (Fly 3 and Fly 4, both heterozygous) are then crossed to produce the F2\text{F}_2F2 generation.
State the genotype of Fly 2.
Complete the cross to find the male gametes and the four offspring genotypes (A, B, C, and D) represented in the table below:
| Female | WWW | www |
|---|---|---|
| Male ? | A | B |
| Male ? | C | D |
Determine the expected phenotypic ratio of normal-winged flies to vestigial-winged flies in the offspring.
What does the term 'heterozygous' mean?
State one reason why the importance of Mendel's work on hereditary factors was not recognized by other scientists in 1866.
Practise AQA GCSE Biology Reproduction with exam-style questions for Foundation and Higher tier. 60 questions covering Sexual and asexual reproduction, Meiosis, Advantages and disadvantages of sexual and asexual reproduction (biology only), DNA and the genome, DNA structure (biology only), Genetic inheritance, Inherited disorders, and Sex determination, matched to the AQA GCSE Biology (8461) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.