Does midpiece length correlate with mitochondrial DNA copy number in the Eurasian Blue tit (Cyanistes caeruleus)?
Sperm morphology can affect the fertilization success of a male and in doing so play an important role in the reproductive success of an individual. Although bird sperm share a common blueprint, (a head containing the nucleus, a midpiece in which mitochondria reside and ATP is stored, and a tail), there is considerable variation in the relative size and morphology of these components among birds. Passerine birds vary drastically in sperm midpiece length and this project aims to get a clearer understanding as to why that might be, and what the functional implications of this variation are.
Sperm cells require energy in the form of ATP to reach and fertilize an egg. In bird sperm cells, ATP is located in the mitochondria (mtDNA), which are wrapped around the sperm midpiece. One theory is that longer sperm midpieces contain more mitochondria and so have a higher energy capacity. A higher energy capacity could provide more power to the swimming sperm cell, which in turn could lead to a higher fertilization success. It is possible to estimate the number of mitochondria by comparing the ratio of mtDNA to nuclear DNA of sperm cells, and then to compare this estimate to the midpiece length of the sperm. For this master thesis, you will test for a correlation between midpiece length and mtDNA copy number in the Eurasian Blue tit (Cyanistes caeruleus).
Project (field and lab)
You will take part in fieldwork at Dæli (near Oslo) in a well-established nest box area, along with other researchers and master students. You will get training in catching and handling of birds, how to perform measurements and ringing, and how to collect sperm samples. There will also be lab work involved where you will learn how to extract DNA from sperm samples and quantify the amount of nuclear and mitochondrial DNA using qPCR, as well as statistical analyses using R/R-studio.
Arild Johnsen, Tore Slagsvold and Marie Danielsen