papers

Question 1

Hurtado et al
What is it about?

Answer 1

• study about the introduction of the Japanese carpet shell into European marine ecosystems
• and study about the resulting hybridization

Question 2

Hurtado et al
What did they do?

Answer 2

• used length differences in major ribosomal RNA gene and minor ribosomal RNA gene for genetic identification
• they did FISH-experiment (=fluorescent in situ hybridization)

Question 3

Hurtado et al
results?

Answer 3

length differences on RNA genes:
- showed evidence that morphological identification was not right in some cases
- genetic identification could identify hybrids that before were morphologically identified as European carpet shell
- FISH-experiment confirmed hybrid nature

–> cytological and genetic evidence for hybrids

• suggest further experiments with species-specific molecular markers to
  (1) detect degree of interspecific hybridization
  (2) detect existence of introgression

Question 4

Farrell et al
What did he do?

Answer 4

• study about recent demographic events and gene flow
• about boarfish-pop.
• why have the boarfish pop. increased?
  –> migration?
  –> local expansion?

Question 5

Farrell et al.
how did he do it?

Answer 5

• he used microsatellites in combination with NGS and GBS (genotyping by sequencing)
• they sampled from
• good study that highlights the combination of different molecular markers
• highlights the use of microsats due to their high allelic richness, mutation rate and statistical power
• detected 40 loci that they used
• they calculated Fit and expected He
• they did cluster-analysis from STRUCTURE analysis and AMOVA

Question 6

Farrell et al.
what are the results?

Answer 6

• there were 7 distinct populations
• there was a lack of migration –> lack of gene flow
• pop. increase was NO result of recent influx
• increase was probably a demographic process (local expansion)
• he emphasizes microsats as generic, cost-effective and rapid method for large-scale studies

Question 7

Cordero et al
what did they do?

Answer 7

• study with microsats and mtDNA
• to assess genetic structure of Manila clam pop.
  –> unraveled their population structure (North America, Japan, Europe)
  –> unraveled history of clam introduction

Question 8

Cordero et al.
what did they find out?

Answer 8

with microsats:
- small overall differentiation
- suggests recent introduction of Manila clam in North America and Europe
- evidence that Japanese Manila clam is ancestor of North American’s and Europe’s

mtDNA
- suggests a strong founder event in European pops
–> because higher differentiation between North American and European clams
than
differentiation between North American and Japanese clams
- reduction in genetic variability in Europe attributed to that founder effect

• study suggests: maybe concealed introduction (especially concerning European pops.) due to recent hatchery practices

Question 9

what does the Manila clam study show in terms of use of genetic markers?

Answer 9

it’s a good study that shows the combination of two diff. markers to understand genetic patterns
(1) in unraveling pop. structure
(2) in unraveling history of clam introduction