Question

Question 2 (11 points) In the plant genus Triticum there are many different polyploid species, as well as diploid species. Crosses were made between three different species, and hybrids were obtained. The meiotic pairing was observed in each hybrid, and this is recorded in the following table. (Hint#1: A bivalent is two homologous chromosomes paired at meiosis, and a univalent is an unpaired homolog at meiosis. HINT #2 : For this question, review your knowledge of chromosome inheritance and pairing in meiosis along with what you learned about auto- and allopolyploids in this module. For review, see pages 591-599 in the textbook.) Species crossed to make hybrid Pairing in hybrid F1 meiosis Cross 1. T. durts × T. mono 7 bivalents  + 7 univalents Cross 2. T. tivum × T. mono 7 bivalents  + 14 univalents Cross 3. T. tivum × T. durts 14 bivalents  + 7 univalents a) Using the information gathered from the crosses above, deduce the F1 chromosome number (ploidy) from each cross. b) Using the information gathered from the crosses above, deduce the somatic chromosome number of each parent species used. c) State which species are polyploid and whether they are autopolyploids or allopolyploids. d) Describe how the observed chromosome pairing pattern arose in the the F1 of Cross 1.0.

Answer 1

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