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Xin Li

  • Associate Professor

PhD

3-8553 Medical Center
(585) 275-6576
xin_li@urmc.rochester.edu

Office Hours: By appointment

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Research Overview

We aim to understand the unique property of germ cells. Germ cells are the only cell type whose lifespan is not limited as they are reprogrammed with totipotency in the next generation. To ensure the sustainability of a species, germ cells need to fulfill three additional new properties that are distinct from any other cell type.

First, the germ cells must faithfully replicate their genome, avoiding invasion from foreign genetic elements, and only recognizing gametes from their own species to fertilize.

Second, the germ cells need to diversify their offspring. Mutations primarily come from meiotic recombination, transposon insertions/deletions, and spontaneous point mutations and structural variations. It has been found that the number of mutations increases with age in men.

Third, some acquired traits are inheritable. Although once discredited, Lamarkian inheritance has been resurrected by recent advances in our understanding of epigenetics. It has been shown that germ cells are sensitive to the environment & can pass epigenetic information across generations.

We want to understand the basic principles underlying these unique properties from two specific angles. The first is through an RNA biology oriented approach. We strive to understand how various germ-line RNAs prepare and shape epigenetic information flowing across generations. The second focuses on comparative biology. We have established alternative model organisms, such as chickens and lizards, for studying germ cell biology. We are adopting an interdisciplinary approach that includes genetics, epigenetics, cell biology, RNA biochemistry, reproductive biology, early embryology, evolutionary biology, and bioinformatics. Currently, our ongoing projects are centered on two related topics: PIWI-interacting RNAs (piRNAs) and sperm RNAs. piRNAs are a recently discovered type of small RNA that offers great promise in advancing our understanding of germ cell biology, whereas sperm RNAs may offer important insight into the transgenerational flow of epigenetic information. Finally, beyond infertility and contraception, what we have learned in germ cells can be applied to other cell types to promote regeneration or anti-aging. At the same time, understanding the mis-activation of some germline properties can offer insight into some diseases, such as cancer.

 

Selected Publications