Yolk androgens and embryo sex: Maternal effects or confounding factors?

Gilbert, Lucy; Bulmer, Elena; Arnold, Kathryn E.; Graves, Jennifer A. Marshall

doi:10.1016/j.yhbeh.2006.10.005

Cited by 34 publications

(20 citation statements)

References 45 publications

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“…No entanto, este trabalho sugere que os pais individualmente contribuem apenas com os seus genes nucleolares e que o efeito, a influência ou a contribuição paterna mensurada como algo extragene nucleolar são tão pequenos quanto insignificantes no sucesso da fertilização e da eclosão. (Hohenboken, 1984;Hiendleder e Wolf, 2003;Royle et al, 2003;Brown et al, 2006;Biard et al, 2007;Garamszegi et al, 2007;Gilbert et al, 2007).…”

Section: Resultsunclassified

Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus)

Allaman

Freitas

Viveiros

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus) RESUMOAvaliou-se o quanto fêmeas e machos contribuem para a variação total das taxas de fertilização e de eclosão em curimba (Prochilodus lineatus). Utilizou-se sêmen criopreservado proveniente de cinco machos para fertilizar ovócitos de seis fêmeas em um esquema fatorial cruzado 5x6, totalizando 30 famílias. Além das características reprodutivas dos machos e fêmeas, foram avaliadas as taxas de fertilização e eclosão para cômputo dos efeitos materno e paterno. Os componentes da variância foram estimados por meio da máxima verossimilhança restrita, sendo construídos intervalos Highest Posterior Density (HPD) para cada componente. Verificou-se que as fêmeas contribuíram muito mais para a variação total em relação aos machos para as taxas de fertilização e eclosão. Para a taxa de fertilização, as fêmeas contribuíram com 26,3% da variação total e os machos com 8,9%. Em relação à taxa de eclosão, as fêmeas contribuíram com 11,9% e os machos com 1,6%. Concluiu-se que houve efeito materno sobre as taxas de fertilização e eclosão e que o efeito paterno avaliado individualmente foi pouco expressivo ou até mesmo insignificante.Palavras-chave: peixe, componentes da variância, efeito parental, índices reprodutivos ABSTRACT The aim of this study was to evaluate how much females and males contribute to the total variation of reproductive traits such as fertilization and hatching rate in curimba

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Section: Resultsunclassified

Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus)

Allaman

Freitas

Viveiros

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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“…Several studies have shown that yolk steroid levels decrease early in embryonic development [26,32] but the reasons for such a decline remain unidentified. Proposed explanations include: dilution of yolk by albumen, leaching of steroids from yolk to albumen and steroid metabolism [4,26]. Our results support the idea that the decline in yolk steroid concentrations is the result of metabolism and not dilution or leaching, since whole egg quantities decline during development.…”

Section: Discussionmentioning

confidence: 99%

“…The YA homogenate ultimately included yolk, albumen and all extra-embryonic membranes. These components were combined into a single homogenate because it was not feasible to separate them at all stages of development [26]. Egg components were homogenized using a Tissue Tearor homogenizer (BioSpec Products Inc., Bartlesville, OK, USA).…”

Section: Methodsmentioning

confidence: 99%

“…In the second treatment, eggs were placed at 48C for 4 days before injection with ([ 3 H]T). This treatment was intended to prevent embryonic development [26] in order to detect if there was any maternal contribution to steroid metabolism. The third treatment was identical to the second treatment except that eggs were placed at 138C, the approximate ambient temperature that unincubated eggs would have experienced in the nest, before injection.…”

Section: (D) Experiments 2: Radioactive Testosterone Distributionmentioning

confidence: 99%

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Embryonic modulation of maternal steroids in European starlings ( Sturnus vulgaris )

2010

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In birds, maternally derived yolk steroids are a proposed mechanism by which females can adjust individual offspring phenotype to prevailing conditions. However, when interests of mother and offspring differ, parent-offspring conflict will arise and embryonic interests, not those of the mother, should drive offspring response to maternal steroids in eggs. Because of this potential conflict, we investigated the ability of developing bird embryos to process maternally derived yolk steroids. We examined how progesterone, testosterone and oestradiol levels changed in both the yolk/albumen (YA) and the embryo of European starling eggs during the first 10 days of development. Next, we injected tritiated testosterone into eggs at oviposition to characterize potential metabolic pathways during development. Ether extractions separated organic and aqueous metabolites in both the embryo and YA homogenate, after which major steroid metabolites were identified. Results indicate that the concentrations of all three steroids declined during development in the YA homogenate. Exogenous testosterone was primarily metabolized to an aqueous form of etiocholanolone that remained in the YA. These results clearly demonstrate that embryos can modulate their local steroid environment, setting up the potential for parent-offspring conflict. Embryonic regulation must be considered when addressing the evolutionary consequences of maternal steroids in eggs.

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“…There is also an interaction in the amount of androgen in the yolk between laying order and sex of the egg. Female eggs laid late in the laying order have significantly more yolk androgens than do male eggs (Gilbert et al 2007). Presumably, this increases the competitive ability and survival of late-hatching female chicks in an asynchronously hatching brood.…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

Mind the gap: the ratio of yolk androgens and antioxidants varies between sons and daughters dependent on paternal attractiveness

Pariser

Gilbert

Hazon

et al. 2011

Behav Ecol Sociobiol

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Females are expected to partition resources between offspring in a context-dependent way to maximise total fitness returns from a reproductive attempt. Female zebra finches (Taeniopygia guttata) vary the allocation of yolk androgens and antioxidants among offspring. Importantly, the balance between androgens and antioxidants in yolks may be more important than their independent absolute amounts in terms of fitness consequences for developing young. Therefore, we tested whether the relative allocation of these two resources in yolks varies according to either the Trivers-Willard, positive or compensatory maternal investment hypothesis. We manipulated male attractiveness using coloured leg bands (red-banded males appear attractive; green-banded males, unattractive) and measured yolk androgens and antioxidants in each egg, egg sex, clutch sex ratio and female condition. While female zebra finches manipulated the balance of androgens and antioxidants within and between clutches in response to mate attractiveness, offspring sex and their own condition, they did not do so in a way that consistently followed any of the hypotheses. Mothers paired with unattractive males allocated a larger antioxidant/ androgen ratio to daughters than sons. This pattern was reversed when paired to an attractive male; sons received a larger antioxidant/androgen ratio than daughters. We also found offspring sex ratio decreased with increasing female condition for unattractive males, but not for attractive males. However, without knowing the fitness consequences of the balance of different egg constituents, it is difficult to interpret the patterns consistently in terms of the Trivers-Willard, compensatory and positive investment hypotheses.

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Yolk androgens and embryo sex: Maternal effects or confounding factors?

Cited by 34 publications

References 45 publications

Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus)

Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus)

Embryonic modulation of maternal steroids in European starlings ( Sturnus vulgaris )

Mind the gap: the ratio of yolk androgens and antioxidants varies between sons and daughters dependent on paternal attractiveness

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