A gene showing codominance: a) has alleles that are recessive to each other b) has both alleles independently expressed in the heterozygote c) has one allele dominant to the other d) has alleles tightly linked on the same chromosome e) has alleles expressed at the same time in development 2. The ABO blood groups in humans are determined by a multiple-allele system in which I* and I are codominant and are both dominant to 1. A newborn infant is type A. The mother is type O. Possible phenotypes of the father are a) A, B, or AB. b) O only. c) A or AB. d) A or O. e) A, B, or O. 3. Which statement about complementary base pairing is not true? a) In DNA, T pairs with A. b) Purines pair with purines, and pyrimidines pair with pyrimidines. c) Complementary base pairing plays a role in DNA replication d) In DNA, C pairs with G. e) The base pairs are of equal length. The phenomenon of "independent assortment" refers to: a) expression at the same stage of development b) association of a protein and a DNA sequence implying related function c) unlinked transmission of genes in crosses resulting from being located on different chromosomes, or far apart on the same chromosome. d) association of an RNA and a protein implying related function e) independent location of genes from each other in an interphase cell Mendel's law of segregation, as applied to the behaviour of chromosomes in meiosis, means that: a) pairing of homologous chromosomes will convert one allele into the other, leading to separation of the types. b) alleles of a gene separate from each other when homologous chromosomes separate in meiosis I, or in meiosis II if there is a single crossover between the gene and the centromere. c) genes on the same chromosome will show 50% recombination d) alleles of a gene will be linked and passed on together through meiosis 5.