Question
#2 please
paper 1. During meiosis, crossing over occurs between: a) homologous chromosomes during meiosis II b) non-homologous chromosomes during meiosis II non-homologous chromosomes during meiosis T a) homologous chromosomes during meiosis I 2. A ratio of 13:3 in the F2 generation is indicative of: b) lethality a) complete dominance c) epistasis- 2 genes d) epistasis-3 genes 3. Codgminance results in: a) joint expression of two alleles ) intermediate expression of two alleles c) sometimes dominance, sometimes recessiveness d) none of the above 4. In Drosophila, fused veins is inherited as an X-linked recessive If a fused vein male is crossed with a heterozygous female phenotypes of the Floffsring will be: a) all fused vein ( all wild type
Explanation / Answer
1. D. Homologous chromosomes during meiosis I.
Crossing over occurs between non sister chromatids of homologous chromosmes in meiosis I.
2. C. Epistasis 2 genes.
3. A. Joint expression of two alleles.
Codominance refers to the equal expression of two alleles.
4. B. One fused 3 normal .
Since it is an x linked recessive disorder, fused vein male (XfY) mated with heterozygous female(XFXf) will produce;
XFXf x XfY.
Offsprings; XFXf, XfXf , XFY, XfY.