# Tracking the Rapid Evolution of Sex Chromosome Palindromes and Their Genes

> **NIH NIH F31** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2021 · $38,807

## Abstract

ABSTRACT
In many species, genes and genomic regions involved in male fertility evolve rapidly. Mammalian sex
chromosomes are enriched for rapidly evolving large palindromic sequences harboring testis-specific genes.
However, the mechanism driving rapid evolution of X- and Y- palindromes and their associated genes is poorly
understood. I propose that intra-palindrome gene conversion – the “copying” of sequence from one palindrome
arm to the other via recombination – is the primary mechanism driving X- and Y- palindrome evolution. The
premise of this proposal is based upon observations from my recently published findings in mouse and previous
studies in primates that X- and Y-palindromes, respectively, undergo on-going intra-palindrome gene conversion.
To address the rapid evolution of X- and Y-palindromic sequences, I will first identify whether selective pressures
(i.e. positive or purifying selection) influence the sequence evolution of X- and Y- palindromes in mice. This will
be the first systematic analysis of both X- and Y-palindrome sequence evolution within a single species to
understand the selective pressures governing their evolution. I will also develop a novel assay to address, for
the first time, the in vivo frequencies of X- and Y- intra-palindrome gene conversion. Understanding the evolution
of X- and Y- palindromes and in vivo frequencies of intra-palindrome gene conversion will provide valuable
insights into the rapid evolution of genomic regions important for male fertility.

## Key facts

- **NIH application ID:** 10140883
- **Project number:** 1F31HD104339-01
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Callie Swanepoel
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $38,807
- **Award type:** 1
- **Project period:** 2021-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10140883

## Citation

> US National Institutes of Health, RePORTER application 10140883, Tracking the Rapid Evolution of Sex Chromosome Palindromes and Their Genes (1F31HD104339-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10140883. Licensed CC0.

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