Nicotiana tabacum is presumed to be an allotetraploid originating from a cross between N. sylvestris (the S genome) and N. tomentosa (the T genome). Each of the two parental species (2n = 24) contributed 12 chromosomes (S & T), which then doubled to form the 24 pairs of chromosomes observed in N. tabacum. a) Diagram the entire cross starting with the original parents until the formation of N. tabacum. Distinguish between chromosomes of N. sylvestris and N. tomentosa and give the chromosome number of all individuals in the cross. Include gametes in your crosses. b) A monosomic N. tabacum is crossed with N. sylvestris and produces offspring, some with 36 chromosomes and some with 35 chromosomes. Using cytological examination at meiosis, the 35-chromosome types show 11 bivalents and 13 univalents. Is this plant monosomic in the S or T genome? Show why it cannot be the other genome as part of your solutions

Nicotiana tabacum is presumed to be an allotetraploid originating from a cross between N. sylvestris (the S genome) and N. tomentosa (the T genome). Each of the two parental species (2n = 24) contributed 12 chromosomes (S & T), which then doubled to form the 24 pairs of chromosomes observed in N. tabacum. a) Diagram the entire cross starting with the original parents until the formation of N. tabacum. Distinguish between chromosomes of N. sylvestris and N. tomentosa and give the chromosome number of all individuals in the cross. Include gametes in your crosses. b) A monosomic N. tabacum is crossed with N. sylvestris and produces offspring, some with 36 chromosomes and some with 35 chromosomes. Using cytological examination at meiosis, the 35-chromosome types show 11 bivalents and 13 univalents. Is this plant monosomic in the S or T genome? Show why it cannot be the other genome as part of your solutions

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter11: The Basic Principles Of Heredity

Section: Chapter Questions

Problem 11TYU: Individuals of genotype AaBb were mated to individuals of genotype aabb. One thousand offspring were...

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