2 The Chromosome Theory of Heredity Traits are determined by pairs of genes (alleles)A pair of genes are located on a pair of chromosomes, one gene for each trait on each chromosome of a pair.In meiosis, the chromosomes and therefore the genes, segregate independently – one of each pair to a gameteIn fertilization, gametes unite resulting in a fertilized egg that has two genes for each trait carried on pairs of chromosomes.
16 G: D. HAPLOID –DIPLOID CONDITION IN HONEYBEES: P: (QUEEN) ♀ 2n= (DRONE) ♂ n= 12G:meiosismitosiseggsnnnnspermnnfertilizationparthenogenesisFemale larvae (2n)Differentiaton due to difference in dietMale larvae (n)QUEENWORKERSDRONES
17 In some species of animals, sex is determined by environmental conditions or by the presence or absence of the opposite sexBonellia, If there is more of female individuals in the population, the larva develops into male, which is very small and lives as a parasites in the reproductive system of the female.In amphibians sex determination is affected by temperature of the environment, and also by hormones.
18 In certain annelids, when the number of segments of the organism is small, it is a male. When the number of segments increase, the organism becomes female.
26 1. Determine if the trait recorded in the pedigree below is dominant or recessive and sex-linked or not. Which of the lettered individuals carry an allele for the trait.abcdef
27 2. Determine if the trait recorded in the pedigree below is dominant or recessive. Is it sex-linked or not?bdeac
28 3. Below is a pedigree for four generations of a family, some of whose members exhibit a particular trait. From the information in the pedigree, determine if the trait is dominant or recessive, and sex –linked or not sex-linked. Which of the lettered individuals is a carrier- that is, heterozygous-for the trait?acbd
29 4. Determine if the trait recorded in the pedigree below is dominant or recessive and sex-linked or not. Which of the lettered individuals are heterozygous for the trait?bacfed
30 5. The pedigree below shows the blood types of some individuals 5. The pedigree below shows the blood types of some individuals. List all the possible genotypes of each lettered individuals.OABedABabcf