lunes, 28 de marzo de 2016

Viability of Booby Offspring is Maximized by Having One Young Parent and One Old Parent

Drummond H, Rodríguez C (2015) Viability of Booby Offspring is Maximized by Having One Young Parent and One Old Parent (A Widdig, Ed,). PLOS ONE, 10, e0133213.

It is widely expected that the quality of offspring will vary with the age of their parents and
that this variation should influence animals’ choice of mates. However, theoretical predictions
for age effects are contradictory and, to our knowledge, we do not know for any wild
animal how the quality of offspring is affected by both parents’ ages across their lifespans,
or whether mothers’ and fathers’ ages interact. We tackled this question using long-term
data on a highly philopatric, insular population of the blue-footed booby (Sula nebouxii). In
this species extra-pair paternity is most common in pairs of two young parents or two old
parents, implying that these age combinations might prejudice offspring quality. Analysis of
the viability of 3,361 offspring of parents up to 21 years old revealed that fledglings with two
young parents or two old parents were least likely to become breeders, whereas fledglings
with one young parent and one old parent were most likely to do so. For young parents of
either sex, offspring viability increased with age of the other parent; for very old parents, it
decreased. These effects could be mediated by parents flexibly modifying their investment
in offspring in response to their own and their partners´ ages, but evidence for this was lacking.
In 5,343 breeding attempts, although mothers’ and fathers’ ages independently affected
four heavily care-dependent breeding traits at the clutch and nestling stages, their interaction
did not affect any trait. The effects of parental age combinations on viability could also
be mediated by genes: fledglings with one young parent and one old parent could benefit
from greater heterozygosity or better genes. 

Seleccionado por: Verónica G

Yo estoy enfocada un poco más en el área de la conducta, por lo que me interesa revisar este artículo ya que es una de las bases de mi proyecto y dado que soy inexperta en el área de molecular y genómica quiero ver si me dan ideas o comentarios
Este artículo habla sobre el efecto en la viabilidad de las crías de pajaros bobos al combinarse las edades parentales.
A mi me interesa saber si el combinar las edades de los padres puede incrementar la Heterocigosis de las crías y si las hembras incurren en
copulas extra pareja para incrementar dicha heterocigosis.
Es un artículo que a mi parecer es bastante interesante aunque no habla tanto de molecular, espero les guste.

lunes, 7 de marzo de 2016

Can DNA-Based Ecosystem Assessments Quantify Species Abundance? Testing Primer Bias and Biomass—Sequence Relationships with an Innovative Metabarcoding Protocol

Elbrecht V, Leese F (2015) Can DNA-Based Ecosystem Assessments Quantify Species Abundance? Testing Primer Bias and Biomass—Sequence Relationships with an Innovative Metabarcoding Protocol. PLOS ONE, 10, e0130324.

Seleccionado por: Nancy


Metabarcoding is an emerging genetic tool to rapidly assess biodiversity in ecosystems. It
involves high-throughput sequencing of a standard gene from an environmental sample
and comparison to a reference database. However, no consensus has emerged regarding
laboratory pipelines to screen species diversity and infer species abundances from environmental
samples. In particular, the effect of primer bias and the detection limit for specimens
with a low biomass has not been systematically examined, when processing samples in
bulk. We developed and tested a DNA metabarcoding protocol that utilises the standard cytochrome
c oxidase subunit I (COI) barcoding fragment to detect freshwater macroinvertebrate
taxa. DNA was extracted in bulk, amplified in a single PCR step, and purified, and the
libraries were directly sequenced in two independent MiSeq runs (300-bp paired-end
reads). Specifically, we assessed the influence of specimen biomass on sequence read
abundance by sequencing 31 specimens of a stonefly species with known haplotypes spanning
three orders of magnitude in biomass (experiment I). Then, we tested the recovery of
52 different freshwater invertebrate taxa of similar biomass using the same standard barcoding
primers (experiment II). Each experiment was replicated ten times to maximise statistical
power. The results of both experiments were consistent across replicates. We found
a distinct positive correlation between species biomass and resulting numbers of MiSeq
reads. Furthermore, we reliably recovered 83% of the 52 taxa used to test primer bias. However,
sequence abundance varied by four orders of magnitudes between taxa despite the
use of similar amounts of biomass. Our metabarcoding approach yielded reliable results for
high-throughput assessments. However, the results indicated that primer efficiency is highly
species-specific, which would prevent straightforward assessments of species abundance
and biomass in a sample. Thus, PCR-based metabarcoding assessments of biodiversity
should rely on presence-absence metrics.

Elegí este artículo porque me viene de perlas ahora que estoy en medio del establecimiento de un buen diseño de protocolo a seguir, para la parte experimental de mi proyecto de investigación. 1) Saber si la cantidad de ADN afecta en la diversidad en la comunidad de insectos. 2) Saber si realizar la extracción con nitrógeno líquido o TissueLyser afecta de alguna manera esta diversidad. Esto y otros puntos espero discutir con ustedes.