<span>It's because the genome has undergone mutation which means the foetus has a post anal tail and when the fetus matures the genome triggers absorption in development to remove unnecessary components by disintegrating the unnecessary cells (webbing, tail, etc). When this is not removed it is because the genome did not send the signal for absorption.</span>
50% of their offsprings will have the recessive trait because if you use Punnett square to analyze the data you will see that only 50% of their children will have Tt as their allele
