Parthenogenesis: Fruit Flies Genetically Modify for Asexual Reproduction

Context

Recently researchers at Cambridge University and the California Institute of Technology made a big advance by designing a sexually reproducing fruit fly species to reproduce asexually.

Scientists Genetically Modify ‘Sexual’ Fruit Fly to Reproduce Asexually

• Fruit flies (Drosophila melanogaster): They have long been preferred by genetics researchers due to their appropriateness as model organisms, resulting in major advances in biology and evolution.
• Research: Decades of intensive research with fruit flies has yielded insights into genetics, development, behavior, and other biological processes.

What is Parthenogenesis?

• About: Parthenogenesis is the process of reproduction without fertilization by males, which produces offspring from unfertilized eggs.
• Species in which Parthenogenesis takes place: Some species, such as Drosophila mangebeirai and Drosophila mercatorum, have facultative parthenogenesis, which allows isolated virgin females to generate young without mating, albeit only a portion of the time.

Creating Asexual Reproduction

• Genetic Manipulation: To create asexual reproduction in a type of fruit fly that reproduces sexually, researchers used genetic engineering techniques.
• Biological Repercussions: The effective modification had significant biological repercussions that demonstrated the adaptability and plasticity of genetic systems.

Parthenogenesis Related Genes

• Goal of the study: The goal of the study was to pinpoint the genes that allow Drosophila mercatorum unfertilized eggs to develop parthenogenetically.
• RNA Sequencing: 44 genes that showed differential expression during parthenogenetic development relative to sexually reproducing circumstances were found in D. mercatorum eggs using RNA sequencing.
• Alteration: By overexpressing the polo and Myc genes and downregulating the expression of the Desat2 gene, researchers altered the gene expression levels in D. melanogaster.
  • About 1.4% of the eggs underwent this modification, resulting in adult flies that could reproduce through mating.

Polar Bodies Role

• Chromosome Transmission: An egg receives one pair of chromosomes from each parent during fertilization, which causes polar bodies to form.
• Normal Development: When the male and female pronuclei merge to begin the process of embryonic development, polar bodies are normally eliminated.
• Modified Protein Levels: It’s possible that the modification of polo, Myc, and Desat2 protein levels interfered with the removal of polar bodies, allowing them to participate in the development of the embryo.

Gene Expression and Genomic Structure

• DNA structure: Adenine-thymine and Cytosine-Guanine are base pairs that form a double helix, and DNA is made up of two strands with phosphate-sugar backbones.
• Melanogaster Genome: The genome of Melanogaster is made up of four DNA molecules that have a base pair count of about 200 million, which means that it can encode roughly 13,600 genes.
• RNA Structure: During transcription, base pairs (adenine-uracil and cytosine-guanine) in RNA create complementary sequences to DNA. RNA is single-stranded and contains ribose sugar.

Protein Synthesis and Gene Function

• Genes: DNA segments with thousands of base pairs that include instructions on how to make particular proteins. 
• Transcription:A-U and C-G complementary base pairing is used in the transcription process, which converts DNA sequences into RNA molecules.
• Translation: Based on the genetic code, ribosomes translate RNA molecules into sequences of amino acids that make proteins.

Consequences of Parthenogenesis

• Biochemical Insights: Knowledge of the mechanisms underpinning fruit fly parthenogenesis offers insights into the biology of reproduction and evolutionary adaptations.
• Technological Advancements: This discovery provides new methods for researching genetic regulatory mechanisms and reproductive strategies, opening up new directions for genetic and developmental research.
• Ethical Considerations: The ethical ramifications of asexually reproducing organisms should be carefully considered, as with any genetic alteration.

News Source: The Hindu

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