Complete the Statements (Fill in the blanks)

1. Mendel used _____________ (organism) which is naturally _____________ (pollination type).
2. The F2 phenotypic ratio of a monohybrid cross (complete dominance) is :.
3. The F2 genotypic ratio of a monohybrid cross is ::_____.
4. In a test cross of a heterozygous individual (Tt × tt), the ratio of dominant to recessive offspring is _____________.
5. The Law of _____________ states that alleles of different genes assort independently during gamete formation, provided they are on _____________ chromosomes.
6. Snapdragon flowers showing pink colour in F1 (from red × white parents) is an example of _____________ dominance.
7. Blood group _____________ demonstrates co-dominance because both _____________ alleles are expressed equally.
8. The genotype $I^A$ $I^B$ produces blood group _____________ with _____________ antigens on RBCs.
9. Blood group O can serve as a universal _____________ because it has _____________ $\frac{no}{both}$ antigens.
10. _____________ is the phenomenon where one gene affects multiple traits; an example is _____________ in sickle cell anemia.
11. _____________ inheritance occurs when many genes with additive effects control one trait, producing _____________ variation.
12. Gene linkage was demonstrated by _____________ using _____________ (organism).
13. Recombination frequency measures _____________ between genes on the same chromosome.
14. The chromosomal theory was proposed by _____________ and _____________.
15. The modified dihybrid F2 ratio _____________ results from complementary gene interaction; the example organism is _____________.

Answer Key

1. Pisum sativum; self-pollinating
2. 3 : 1
3. 1 : 2 : 1
4. 1:1 (50% dominant : 50% recessive)
5. Independent Assortment; non-homologous (different)
6. Incomplete
7. AB; $I^A$ and $I^B$
8. AB; both A and B
9. Donor; no (zero) antigens
10. Pleiotropy; HbS allele
11. Polygenic; continuous
12. Thomas Hunt Morgan; Drosophila melanogaster
13. Physical distance (relative) / the genetic distance between genes
14. Sutton; Boveri
15. 9:7; sweet peas (Lathyrus odoratus)