.@Genome_gov researchers have assembled the first, fully complete human #YChromosome sequence! This sequence reveals genetic factors with implications for fertility. (Thread)

While scientists filled in the gaps of the other 23 human chromosomes last year, more than 50% of the Y chromosome’s sequence remained a mystery.

All chromosomes have repetitive regions, but the Y chromosome has an unusually repetitive DNA sequence, which made it particularly difficult for scientists to study!

#T2T researchers applied new DNA sequencing technologies and sequence assembly methods to help tackle the Y chromosome's tricky sequence!

Though the Y chromosome is often associated for its role in sexual development, the factors involved in human sexual development are spread across the genome and very complex, giving rise to the array of human sex characteristics found among male, female and intersex individuals.

These categories are NOT equivalent to gender, which is a social category.

By completing the Y chromosome sequence, researchers were able to better study a region of DNA with genes involved in sperm production. The new sequence showed how DNA can be rearranged in this region, which can affect fertility.

With this new sequence, researchers can find new genomic variations on the Y chromosome, and by studying these variants, scientists can better understand how the Y chromosome contributes to human health.

Learn more about the newly completed #YChromosome sequence!

The research study proves why males are quite predictable. “While all human chromosomes contain repeats, about 30 million letters of the Y chromosome are repetitive sequences.”

@NIH Absolutely groundbreaking.