Dogs have 78 chromosomes in their diploid cells. How many chromosomes are in their haploid cells?

There are ##39## chromosomes in their haploid cells.

During I, the ##78## chromosomes in a diploid cell line up at the equator of the cell. Note that the chromosomes have already replicated.

##39## chromosomes will then move to each pole of the cell. The difference between anaphase in meiosis I and is that in meiosis I, the centromere does not split, so the sister chromatids are still held together.

The result is ##39## chromosomes at the poles of the cell. The chromosome number is reduced from ##2n## (diploid) to ##n## (haploid). Then the cell will undergo meiosis II, where the cell will divide, producing ##4## haploid daughter cells with half the number of chromosomes of the parent cell.