# DBT JRF 2020 — Question 26

Exam: DBT JRF 2020 · Section: B · Topic: Biotechnology · Difficulty: Hard

## Question

'Cybrids' are produced by

## Options

- **A.** fusion of nuclear genomes
- **B.** in vitro fusion of gametes
- **C.** fusion of plastids
- **D.** in vitro fusion of cytoplasm

## Answer

Option D

## Explanation

RNA Polymerase II (Pol II) is responsible for transcribing protein-coding genes (mRNA precursors, pre-mRNA) and several non-coding RNAs. Pol II transcribes: all mRNA (protein-coding); most snRNAs (small nuclear RNAs involved in splicing); miRNAs (microRNAs, most are embedded in Pol II transcripts); snoRNAs in some cases; enhancer RNAs (eRNAs). RNA Polymerase III (Pol III) transcribes: tRNA (all), 5S rRNA, 7SL RNA, U6 snRNA, some miRNAs. RNA Polymerase I (Pol I) transcribes: 28S, 18S, and 5.8S rRNA. Therefore tRNA and 5S rRNA are NOT transcribed by Pol II — they are Pol III products.

Source: https://mypyqbuddy.com/questions/cybrids-are-produced-by-6a05a8a02adafec470293232