Why mammals genomes are way longer than simple organisms, such as birds and insects, even though the number of genes is not that different?

What genomes of animals have scientists sequenced and what are some resulting discoveries?

The accuracy of DNA replication in the human germ-cell line is such that on average only about 0.6 out of the 6 billion nucleotides is altered at each cell division. Because most of our DNA is not subject to any precise constraint on its sequence, most of these changes are selectively neutral. Any two modern humans picked at random will show about 1 difference of nucleotide sequence in every 1000 nucleotides. suppose we are all descended from a single pair of ancestors—Adam and Eve—who were genetically identical and homozygous (each chromosome was identical to its homolog). Assuming that all germ-line mutations that arise are preserved in descendants, how many cell generations must have elapsed since the days of Adam and Eve for 1 difference per 1000 nucleotides to have accumulated in modern humans? Assuming that each human generation corresponds on average to 200 cell-division cycles in the germ-cell lineage and allowing 30 years per human generation, how many years ago would this…

Why The Arrangement of Genesin the Genome Is Not Uniform?

Which of the following best explains the number of similarities between the amino acid sequences of the Drosophila Hedgehog protein and the Chicken Indian Hedgehog protein? O A. The Drosophila hedgehog gene evolved from hedgehogs, which are distantly related to birds. O B. Both genes evolved from a gene present in the last common ancestor of Drosphila and chickens, and the number of differences reflects the amount of time that has elapsed during the evolution of these two lineages. a During the evolution of Drosophila and chickens, a hedgehog like gene arose independently in each lineage, then the gene that arose in chickens diversified. A These genes are unrelated, and the fact that they are similar is only because the proteins need to have similar biochemical properties. They are unrelated because chickens don't have segments and Drosophila larvae don't have limb buds.