Which of the following is not part of genetic "linkage mapping"?
a. calculating recombination frequencies using a testcross
b. assuming that recombination frequency is proportional to the distance
between two linked genes
c. finding and studying alternative (e. g., mutant) phenotypes of a character
d. using information on dna sequences
e. studying characters two at a time

The correct answer is option D.

Explanation:

Linkage mapping is the mapping process in which the genes present on the chromosomes are mapped on the base of their linkage. The linkage mapping helps in calculating how frequent recombination occurs using testcross.

Linkage mapping does not utilize the information that is on DNA sequences, however, it helps in assuming the distance of two linked genes is proportional of the recombination frequency. By the recombination, frequency mutations can be found and study.

Thus, the correct answer is option D.

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.