What are lethal genes?
When lethal genes are present in the organism's chromosomes, the organism is unable to survive. Semi Lethal genes are harmful to the organism but does not cause Death. E.g Huntington Chorea in human
With most lethal genes in hamsters where both germ cells contain the mutant gene death or significant deformity results, but where only one germ cell contains the mutant gene the resultant offspring are healthy. A lethal gene is created when a mutation carries a "double helping" of a particular gene. The result will be the death of the hamster. The only lethal genes currently known that the average pet owner might come into contact with…
A lethal dominant gene prohibits the organism from reproducing irregardless of the paired gene, so it is removed from the gene pool as soon as it appears. A lethal recessive gene, on the other hand, does not prevent reproduction unless it is paired with another lethal recessive, so it may be passed down through many generations before becoming paired and preventing reproduction.