Why in the News
On 17 February 2026 the journal Scientific Data published the first high-quality draft of the genome of Neolissochilus pnar. The paper describes this species as the largest cavefish in the world. It is an endemic species of the limestone caves of Meghalaya.
Species
Neolissochilus pnar (Cyprinidae)
Habitat
Limestone caves of Meghalaya
Features
Lack of pigment; no eyes in adults
What is new
First draft nuclear genome, about 1.56 Gb
Chart: original table.
What Was Done in the Paper?
The researchers sequenced samples taken from the Krem Umladaw caves in the East Jaintia Hills with PacBio long-read technology. According to the paper, the assembly is about 1.56 Gb, has 1,423 contigs, and BUSCO completeness is 99%. The authors say that earlier only the mitochondrial genome and the COI gene of this species were known, not the nuclear genome.
According to the paper, reduction or loss of eyes and lack of colour are common adaptations in cave animals. In this species the juveniles have small eyes and in adults they are not visible externally. According to the authors, its limited habitat makes it vulnerable to extinction because of human activities.
Where Does Confusion Arise in the Exam?
"Sequencing of a genome" does not mean "discovery of a new species". Also, "endemic" means that the species is limited to these caves, not spread over the whole North-East.
Direction of Preparation from Past Questions:
Statement-based questions have appeared in the official General Studies Paper-I of UPSC Prelims 2023. So prepare the species, the habitat and the new point of the study separately. The questions below are original practice questions, not actual PYQs.
Prelims Style: Practice Questions
1. With reference to the genome study of Neolissochilus pnar, consider the following statements:
Statement 1: It is described as an endemic species of the limestone caves of Meghalaya.
Statement 2: The species has been described for the first time in this paper.
Statement 3: The genome was sequenced with PacBio long-read technology.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
See answer and reason
Answer: (b) Only two. Statements 1 and 3 are correct. This paper is about the genome; the species was already known.
2. According to the paper, on what basis is N. pnar mainly separated from its closest species?
(a) Lack of pigment and eyes not being visible in adults
(b) Living in sea water
(c) Having twice the number of fins
(d) Migrating in Himalayan rivers
See answer and reason
Answer: (a). In the abstract, lack of pigment and the absence or reduction of eyes are given as the main difference.
3. According to the paper, which is the closest relative of N. pnar?
(a) Neolissochilus hexastichus
(b) Gangaichthys indonepalicus
(c) Tor putitora
(d) Labeo rohita
See answer and reason
Answer: (a). In the paper, N. hexastichus is placed in the comparison as the closest relative species.
Sources:
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