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Nekateri reprodukcijski in populacijski parametri pri grški kornjači (Testudo hermanni) v ujetništvu
ID Stvarnik, Mateja (Avtor), ID Dovč, Alenka (Mentor) Več o mentorju... Povezava se odpre v novem oknu

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Izvleček
Skozi triletni monitoring smo v aktivni reprodukcijski sezoni preučevali samice grške kornjače (Testudo hermanni boettgeri). Samci so bili prisotni prvo leto, do prvega parjenja. Spremljali smo odstotek izleganja jajc pri samicah v posameznem letu in v posameznem gnezdu. Jajca smo individualno sledili do izvalitve. Po končani inkubaciji smo pregledali valilniški ostanek. Ocenili smo naslednje parametre: oplojenost in vzroke zamiranja kot so inficiranost in dehidriranost. Ugotovili smo, da se ob odsotnosti samcev vsako leto zmanjšuje tako število jajc kot število gnezd na samico. Proučevali smo kemijsko sestavo jajc grške kornjače. Oleinska kislina je predstavljala več kot polovico maščobno kislinske sestave v rumenjaku. V beljaku smo med 18 različnimi aminokislinami ugotavljali največ glutaminske in asparaginske kisline. Med elementi v sledeh smo v lupini, beljaku in rumenjaku izmerili najvišje koncentracije železa. Pri grških kornjačah obeh spolov in različne starosti smo v iztrebkih s postopkom ELISA ugotavljali koncentracije progesterona, estradiola in testosterona v iztrebkih (neinvaziven način vzorčenja). Pri spolno aktivnih kornjačah se ta metoda lahko uporablja za dokazovanje aktivnosti reproduktivnih organov pri obeh spolih na podlagi dinamike hormonov. Ugotovili smo, da se le v obdobju izleganja jajc na podlagi nivoja med posameznimi hormoni v iztrebkih odrasle kornjače lahko določi spol. Z genetsko analizo smo kljub omejenemu obsegu biološkega materiala pokazali, da tako na ravni mitohondrijske, kot tudi jedrne DNK, genetska pestrost omogoča identifikacijo genetske strukturiranosti populacij, ki so bile vključene v našo raziskavo. V analizi 188 vzorcev grške kornjače s petih različnih geografskih lokacij v Sloveniji, Hrvaški, Srbiji, Črni gori in Italiji smo našli tri mitohondrijske haplotipe, ki se med seboj razlikujejo na treh nukleotidnih pozicijah znotraj gena za 12S rRNK. Našli smo tudi osebke s heteroplazmijo mtDNK. Genotipizacijo jedrne DNK smo izvedli na 10 mikrosatelitnih lokusih: Test56, Test76, Test21, GmuA19, Leo21, GmuD51, Test71, Leo56, Leo71 in GmuB08. Na osnovi rezultatov analize mikrosatelitnih lokusov smo proučevane populacije lahko razdelili v gruče, ki se ujemajo z geografskim izvorom vzorcev. Za odgovor na vprašanje ali je spol pri Testudo hermanni determiniran z genetskimi dejavniki, smo sekvencirali celoten genom petih spolno zrelih samcev in petih spolno zrelih samic. Analiza celotnega genomskega nukleotidnega zaporedja ne potrjuje obstoja spolnih kromosomov in ne nakazuje večjih strukturnih sprememb v avtosomalnih genomskih regijah, ki so bile pri drugih vrstah dvoživk in plazilcev povezane z diferenciacijo spola.

Jezik:Slovenski jezik
Ključne besede:želve – fiziologija, reprodukcija – genetika, steroidni hormoni spolnih žlez – analize, jajca – kemija, feces – analize, encimsko vezani imunosorbentni test, mitohondrijska DNA – genetika, filogeografija, analiza zaporedja DNA
Vrsta gradiva:Doktorsko delo/naloga
Organizacija:VF - Veterinarska fakulteta
Leto izida:2020
PID:20.500.12556/RUL-125163 Povezava se odpre v novem oknu
Datum objave v RUL:05.03.2021
Število ogledov:1145
Število prenosov:123
Metapodatki:XML DC-XML DC-RDF
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:Some reproductive and population parameters in the Hermann's tortoise (Testudo hermanni) in captivity
Izvleček:
Throughout three years of monitoring, female Hermann's tortoises (Testudo hermanni boettgeri) were observed during the active reproductive season. Males were present in the first year until the first mating. The percentage of females who laid eggs in each year and in each nest was observed. The eggs were individually tracked until hatching. After incubation, the eggshell mortality was analysed. We assessed the following parameters: fertilization and causes of death, such as infection and dehydration. We concluded that due to the absence of males, both the number of eggs and the number of nests per female decrease each year. The chemical composition of the Hermann’s tortoise eggs was studied. Oleic acid presented more than half of the total fatty acid composition in the yolk. In the egg albumen, among the 18 different amino acids that were detected, glutamic acid and aspartic acid were the most common. The highest concentrations of the trace elements measured in the shell, albumen and yolk were iron. In Hermann's tortoise, ELISA was used to analyse the hormone concentrations of progesterone, oestradiol and testosterone in the faeces (non-invasive sampling) of both genders and of different ages. This method can be used in sexually active tortoises in both genders to determine the activity of gonads based on hormone dynamics. In our research, we concluded that only in the egg laying period, based on the ratio of individual hormone levels in adult tortoise faeces, can gender be determined. Despite the limited volume of biological material, genetic analysis showed that at the level of mitochondrial as well as nuclear DNA, the detected genetic diversity enabled identification of the genetic structure of the populations included in our study. In the analysis of 188 samples of Hermann's tortoise from five different geographical locations in Slovenia, Croatia, Serbia, Montenegro and Italy, we found three mitochondrial haplotypes that differ from each other at three nucleotide positions within the 12S rRNA gene. We also found specimens demonstrating mtDNA heteroplasmy. Nuclear DNA genotyping was performed at 10 microsatellite loci: Test56, Test76, Test21, GmuA19, Leo21, GmuD51, Test71, Leo56, Leo71 and GmuB08. Based on the results of microsatellite analysis, the studied populations could be divided into clusters that matched the geographical origin of the samples. To answer the question of genetic determination of sex in Testudo hermanni, we sequenced the entire genome of five sexually mature males and five sexually mature females. Analysis of the entire genomic nucleotide sequence did not support the existence of sex chromosomes in this species and did not indicate major structural variation in the autosomal genomic regions that have been associated with gender differentiation in other amphibian and reptile species.

Ključne besede:turtles – physiology, reproduction – genetics, gonadal steroid hormones – analysis, eggs – chemistry, faeces – analysis, enzyme-linked immunosorbent assay, mitochondrial DNA – genetics, phylogeography, sequence analysis, DNA

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