Question

If a gene is haplosufficient, that means that:

A) one functional copy is sufficient to produce a wild type phenotype
B) a loss of function mutation in the gene will likely be dominant over wild type
C) it is expressed at a higher level than normal
D) there is a copy present on each of our 23 chromosomes
E) a mutation has removed one half of the gene

Answer 1

A gene being haplosufficient indicates that a single functional copy of the gene is enough to maintain the normal (wild type) phenotype in an organism, demonstrating dominance over nonfunctional alleles.

Step-by-step explanation:

If a gene is haplosufficient, that means that one functional copy is sufficient to produce a wild type phenotype. This concept is crucial in understanding the inheritance patterns and the expression of genes in organisms. In the context of lethal alleles, a gene is essential for survival, and having just one functional wild-type allele is enough to sustain life and mask any nonfunctional alleles, making it dominant over nonfunctional alleles.

This situation is in contrast to recessive lethal alleles, where two copies of a nonfunctional allele would lead to the death of an organism. In cases where an individual carries one wild type and one nonfunctional allele (heterozygous), they will still display the wild type phenotype because the single functional copy of the gene provides enough of the gene product, which showcases the principle of haplosufficiency.