(4) TD is due to a lethal mutation
in the same gene that causes achondroplasia, a familiar and far more common form of short limbed dwarfism this is compatible with life.
Veterinary scientists have long suspected that the FIP virus (FIPV) was a lethal mutation
of the feline coronavirus (FECV), a benign and common intestinal virus, but they couldn't identify how this transformation occurred.
If a "recessive lethal mutation
" is defined as a mutation that results mainly in the premature death of homozygous individuals, sickle cell anemia is a recessive lethal condition.
One potentially lethal mutation
occurred when scientists crossed genes from a Brazil nut with a type of bean.
Extrapolation from data on chlorophyll deficiency mutants (reviewed in Klekowski 1992) produces similar estimates of the overall lethal mutation
rate for annual plant species.
In Drosophila melanogaster about n = 5000 loci produce recessive lethal mutations
with an average mutation rate per generation of [Mathematical Expression Omitted] (Simmons and Crow 1977), giving a (diploid) genomic lethal mutation
rate of U = 0.02 per generation.
Induced lethal genomic events (including DSB, chromosomal aberrations, and lethal mutations
) in eukaryotic cells depend on a linear quadratic relationship in absorbed dose, where the probability of repair is an interactive factor (23).
To investigate how many recessive lethal mutations
are carried by humans on average, Ziyue Gao, a graduate student in the Genetics, Genomics and Systems Biology program, and her colleagues worked closely with a group of Hutterites, a religious community that settled in North America in the 1870s.
"We don't yet understand why the number of recessive lethal mutations
might be relatively constant across distantly related organisms," said Gao.