Studying genetics is followed by the solution of tasks. They demonstrate effect of the law of inheritance of genes. The solution of these tasks seems to most of pupils incredibly difficult. But, knowing a decision algorithm, you will easily cope with them.
Instruction
1. It is possible to allocate two main types of genetic tasks. In the first type of tasks genotypes of parents are known. It is necessary to define genotypes of descendants. At first define what the allele is prepotent. Find recessive an allele. Write down genotypes of parents. Write out all possible types of gametes. Connect gametes. Define splitting.
2. In problems of the second type all on the contrary. Here splitting in posterity is known. It is required to define genotypes of parents. Find as well as in problems of the first type what of alleles is prepotent what - recessive. Define possible types of gametes. Determine genotypes of parents by them.
3. To solve a problem correctly, read it attentively and analyze a condition. To define task type, find out how many couples of signs are considered in a task. Pay attention also to that how many couples of genes control development of signs. It is important to find out, homozygous or heterozygotic organisms are crossed what type of crossing. Define, it is independent or linked genes how many genotypes are formed in posterity are inherited and whether inheritance is connected with a floor.
4. Start the solution of a task. Make short record of a condition. Write down a genotype or a phenotype of the individuals participating in crossing. Define and note types of the formed gametes. Write down genotypes or phenotypes of the posterity received from crossing. Analyze results, write down them in a numerical ratio. Write the answer.
5. Remember that to each type of crossing there corresponds special splitting on a genotype and a phenotype. All these data can be found in textbooks or other grants. Write out all formulas on a single sheet and you hold it always near at hand. Also you can use special tables for the solution of tasks in genetics.