The Rh blood group in humans is determined by a gene on chromosome 1. A dominant allele produces Rh+ blood type, and a recessive allele generates Rh-. Elliptocytosis is an autosomal dominant disorder that produces abnormally shaped red blood cells that have a short life span resulting in hereditary anemia. A large family with elliptocytosis is tested for genetic linkage of Rh blood group and the disease. The lod score data below are obtained for the family.

Over what range of θ do lod scores indicate significant evidence in favor of genetic linkage? <>

Key Concepts

Genetic Linkage

Genetic linkage refers to the tendency of genes located close to each other on a chromosome to be inherited together during meiosis. This phenomenon occurs because linked genes are less likely to be separated by recombination. Understanding genetic linkage is crucial for mapping traits and diseases, as it helps determine whether two traits are inherited together more often than expected by chance.

Lod Score

A lod score (logarithm of the odds) is a statistical measure used to evaluate the likelihood of genetic linkage between a trait and a specific genetic marker. A positive lod score indicates that the observed data is more likely under the hypothesis of linkage than under the hypothesis of no linkage. Typically, a lod score of 3 or higher is considered significant evidence for linkage, while a score of -2 or lower suggests no linkage.

Autosomal Dominant Inheritance

Autosomal dominant inheritance is a pattern of genetic transmission where only one copy of a dominant allele is sufficient to express a trait or disorder. This means that an affected individual has a 50% chance of passing the trait to each offspring. Understanding this inheritance pattern is essential for predicting the likelihood of disorders, such as elliptocytosis, appearing in subsequent generations.