Practise inheritance-through-meiosis questions by distinguishing chromosome sets, identifying meiosis stages and explaining how sexual reproduction creates variation.
The house mouse, Mus musculus, has a diploid number of 40 chromosomes.
Fig. 2.1 shows 6 of these chromosomes.
Fig. 2.1
Identify one pair of homologous chromosomes on Fig. 2.1 by drawing circles around two chromosomes.
Fig. 2.2 shows the banding pattern of chromosome pair 11 of M. musculus. The banding pattern is obtained by staining.
Fig. 2.2
Explain why chromosomes, such as those in Fig. 2.2, are described as a homologous pair.
State the number of chromosomes that are present in M. musculus spermatozoa.
M. musculus produces gametes by meiosis. These gametes are genetically different.
There is random fusion of gametes at fertilisation.
Explain why meiosis is important in the life cycle of M. musculus, apart from producing genetically different gametes.
Explain how the random fusion of gametes leads to the expression of rare, recessive alleles.