A European species of marsh grass called Spartina maritima has a diploid number (2n)of 60. A similar species native to North America, S. alterniflora, has 2n = 62. In 1835 the North American species was found growing near the European species in Southampton, England, after being accidentally imported. Occasional sterile hybrids were noted. In 1895 a new species, S. anglica, was first identified at Southampton and subsequently became very common. The new species has been identified as a fertile hybrid of the original two species. What is the 2n chromosome number of the hybrids that formed from the original two species S. maritima and S. alterniflora?

Question

Quizplus · Accepted Answer

The hybrid species S. anglica is fertile, meaning it must have a chromosome number that is either the same or a multiple of the parental species. Since S. maritima has a diploid number of 60 and S. alterniflora has 2n = 62, the hybrid must have a chromosome number that is halfway between the two or a multiple of this number. The only option that fits this criteria is C) 61.

A European Species of Marsh Grass Called Spartina Maritima Has