Neutral mutations tend to accumulate in DNA at a predictable rate; like the ticks of a __________,
they can help researchers estimate how long ago two lineages diverged. Fill in the blank(s) with the appropriate word(s).
molecular clock
You might also like to view...
Genes abc and def have a high average cotransduction frequency. Genes abc and xyz have a very low average cotransduction frequency. What is the best explanation for this difference?
A. The genes abc and def are much closer to each other on the chromosome. B. The genes abc and def must share a higher degree of sequence similarity. C. Both genes have a high affinity for the viral binding sites. D. Both genes code for gene products that are necessary for viral replication.
Morris is a big, healthy bull. One spring, he fathers ten calves, but five of them are stillborn, their muscles very rigid in a phenotype called "contracture." Farm animals often mate with their close relatives. So, three of the dams (mothers of the stillborns) are also Morris' daughters, and the fourth is his half-sister. The large number of stillborns is most likely due to
A) recessive lethal alleles that occur as new mutations in the doomed offspring. B) dominant non-lethal alleles that Morris shares with his mates. C) lethal alleles that Morris shares with his mates. D) co-dominance between two lethal alleles.
Genes that control glucose metabolism are inactivated to study diabetes _____
Fill in the blank(s) with correct word
Which event of fertilization occurs first?
A. the acrosomal reaction B. the entry of sperm DNA into the egg C. the cortical reaction D. cleavage E. vitelline layer hardens