The human Y chromosome itself contains only 78 working genes, compared to close to 1500 working genes on the X chromosome, which is why it is smaller. It's not exactly to scale, but then again, real chromosomes don't have eyes, so a little wiggle room is acceptable.
Made with 100% wool, stuffed with cotton.
Chromosome Pair Amigurumi by ~holls on deviantART
Image credits: ~holls
Art and Science of Laboratory Medicine