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 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

Biology

Agustin Lowe

9 February, 13:30

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 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?

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Answers (1)

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Dana Benton · Answer 1

2 n = 61 Chromosomes

Explanation:

If the plants that are produced are fertile then they must have a chromosome number hybrid of previous two species and that is 122. This is an example of tetraploidy. It is crucial that the chromosome number of the species should be even otherwise the pairing will result in a mismatch and the produced offspring will be a sterile hybrid.