Genetics & Plant Breeding - ICAR JRF/SRF 2024

• Template Strand of DNA:
• The specific single strand of the double-stranded DNA duplex that RNA polymerase reads ($3' \rightarrow 5'$) to synthesize a complementary mRNA molecule ($5' \rightarrow 3'$).
• Also termed the antisense strand or non-coding strand.
• The complementary non-template strand is termed the coding or sense strand. (Correct answer: Option 1)

• Transfer RNA Structural Variation:
• Canonical tRNA molecules consist of 73 to 93 ribonucleotides folded into a cloverleaf secondary structure.
• The cloverleaf core (acceptor arm, anticodon arm, and T$\psi$C arm) is highly invariant in length; the size differences between different tRNAs are caused by variations in the D-arm (di-hydrouridine loop) and the variable extra arm (which can range from 3 to 21 nucleotides). (Correct answer: Option 1)

• Statement (I) is Incorrect: In maize (Zea mays), Stock 6 is a classical maternal (gynogenetic) haploid inducer line developed by Coe (1959); when used as a male pollinator on diploid females, it induces maternal haploid progeny at a frequency of approximately $2-3\%$, not paternal haploidy.
• Statement (II) is Incorrect: Paternal haploid induction (androgenesis) in maize is mediated by the _indeterminate gametophyte_ (_ig1_) mutation (discovered by Kermicle, 1969), which affects female embryo sac development; Stock 6 gynogenesis is governed by mutations in the pollen-specific phospholipase gene qhir1 / MTL / NLD / ZmPLA1, not the ig1 gene.
• Conclusion: Both Statement (I) and Statement (II) are incorrect (Option 2).

Correct option: (2) Both Statement (I) and Statement (Il) are incorrect