Can sexual reproduction create new genetic information?

Question

Is there a small chance that in sexual reproduction a new allele forms in the off-spring that was not present in either of the parents, or are the alleles in the offspring always from at least one of the parents? Is new genetic information ever created during sexual reproduction, or only through mutations during an organisms life time?

Answer 1

It's estimated that every individual contains approximately 15-30 mutations that are entirely unique to them that didn't originate from one of their parents. So, yes, sexual reproduction can result in mutations. Though it should be noted that asexual reproduction too can have mutations -- no form of replication is 100% error proof, because if it was, we'd all still be bacteria. More common mutations in meiosis leads to indels (insertions/deletions) of small segments of the genome, or sometimes entire segments of chromosomes containing several genes. This is because of how recombination works. Recombination can only happen between homologous sequences, but due to the modular nature of genes (that is, very diverse and far away genes may nevertheless share high sequence homology) means that recombination isn't always symmetrical, which will always leave some gametes with extra or less genetic material. This may be entirely benign or cause considerable distress in offspring (assuming they survive). One example is called 16p11.2 deletion syndrome, were a small segment of chromosome 16, around the center, is deleted. This deletes a handful of genes associated with normal intellectual development and learning; many such children with this syndrome also fall along autism spectrum disorder. As you noted, mutations can also be generated somatically during lifetime off the offspring. These are known contributers to diseases (especially, though not exclusively, to cancer). Additionally, t- and b- cell lymphocytes purposely edit parts of their genomes to recognize pathogens. Thus, every single t- and b- cell in your body is genetically distinct from you (though still over 99% similar to other somatic cells).