27. (4 PTS) You are studying pollination in the plant Arabidopsis, and you have found a mutation in a gene for stamen length that produces a very long stamen in these flowers. You are interested in crossing these to a mutation from a different lab that produces shorter petals, to see how this combination would affect pollinators like honey bees. When you look these genes up you find they are 24cM apart on Chromosome 12. You contact the other lab and they send you their true-breeding plants with short petals and normal stamens. You cross these to your long stamen plants, and all of the F1’s have short petals and normal stamens. You then cross the F1’s to your long stamen plants. If you collect 100 plants from this cross how many do you expect to have short petals and long stamens?

12

Explanation:

Parent 1 : normal petal, long stamen

Parent 2 : short petal, normal stamen

F1 generation has all short petal and normal stamen plants so these two are the dominant traits.

F2 generation will have a mixed progeny. Out of them normal petal, long stamen and short petal, normal stamen will be parental combinations since they were the phenotype of the original parents.

Distance between the two genes is 24 cM and distance between genes = recombination frequency. Hence, recombination frequency here is 0.24.

Out of 100 total plants in F2, 100*0.24 = 24 will be recombinants. Out of 24, 12 will be short petal, long stamen recombinants and other 12 will be normal petal, normal stamen recombinants.

Hence, out of 100 plants 12 are expected to have short petals and long stamens.

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.