In combination with healthy alleles. See Silent Mutations.
The Lethal Aspect of the allelic mutation becomes apparent only when two defective alleles combine to form the Bi-Chromosomal Defective Variant. Phenotypic discrepancies are expected.
Lethal dominant alleles are less common than lethal recessive alleles because individuals with lethal dominant alleles typically die before they can pass on the harmful gene to their offspring, reducing the frequency of the allele in the population. In contrast, individuals with lethal recessive alleles can carry the gene without showing symptoms, allowing the allele to persist in the population through carriers who can pass it on to their offspring.
A typical human would have around 1-2 lethal genes if homozygous for lethal alleles. Lethal genes are usually rare in the human population due to the negative impact on survival and reproduction.
A lethal allele is maintained in population for example when you use bug spray on cockroaches there will be at least one cockroach with an allele that protects it from the bug spray, it then breeds and the allele Is passed to it's offspring and they will also be immune to the pesticide. Those babies will most likely breed with each other when they are mature passing on the allele from both of the parents making the offspring 100% immune. It's the same concept for lethal alleles.
Lethal dominant alleles normally die before obtaining the ability to reproduce.
Huntington's disease, where the lethal allele expresses itself very late in an individuals life. Persons carrying the dominant lethal allele does not become aware of the disease until after their reproductive age. Thus, they pass the lethal allele to their children without knowing and the allele persists.
If both parents carry the trait then there is a only a 25 percent chance the pregnancy will abort but there is a 75 percent chance the child will carry the trait and that can cause abnormalities during the pregnancy and afterwards.
If the lethal gene is recessive, and the parent carrying it is heterozygous for that gene, it can be passed down to offspring in the recessive form. If the mate of the parent happens to be carrying the same gene heterozygously, 50% of offspring will be expected to inherit the recessive lethal gene heterozygously. 25% of the offspring will be expected to inherit the lethal gene homozygously, leading to death. The remaining 25% of offspring we will expect to homozygously inherit the non-lethal gene. 1:2:1 ratio
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.
a woman who is heterozygous for the gene
depends if its autosomal or dominant or what. I need a little more info
Recessive alleles are only expressed in the phenotype if the organism is homozygous for the recessive allele (assuming diploidy). If the trait is sex-linked, then it will always show up in males if passed.
it was very lethal. symptoms are bloody vomit fever and tumors.