Genetic Crosses 0.0 / 5 ? BiologyDNA and inheritanceIGCSEAQA Created by: Nicole DCreated on: 07-12-13 19:25 Genetic Crosses 10 Questions 1 of 12 What is the genetic cross? A conventional pattern for describing the results of breeding experiments 2 of 12 Consider a cross between a homozygous tall pea plant with a homozygous dwarf pea plant So if we used the letter 'h' ... 3 of 12 What would 'H' represent? The dominant allele for a tall plant 4 of 12 Therefore what would 'h' represent? The recessive allele for a dwarf plant 5 of 12 What are the parents' phenotypes? Tall and dwarf 6 of 12 What are the parents' genotypes? HH and hh 7 of 12 What are the different types of gametes they can make? H, H, h, and h 8 of 12 Draw out the genetic diagram for the possible offspring . 9 of 12 Therefore, what is the expected offspring? 100% tall pea plant (heterozygous) 10 of 12 Now consider a cross between 2 heterozygous pea plants, what would the offspring be? 75% tall, 25% dwarf / 25% homozygous dominant, 50% heterozygous, 25% homozygous recessive 11 of 12 What ratio of the dominant allele to the recessive allele in this second generation? 3 : 1 ---> dominant : recessive 12 of 12
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