scholarly journals Temporal Variation in the Genetic Composition of an Endangered Marsupial Reflects Reintroduction History

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 257
Author(s):  
Rujiporn Thavornkanlapachai ◽  
Harriet R. Mills ◽  
Kym Ottewell ◽  
J. Anthony Friend ◽  
W. Jason Kennington
Keyword(s):  
Genetic Variation ◽  
Genetic Relatedness ◽  
Allelic Diversity ◽  
Genetic Composition ◽  
Effective Population ◽  
Breeding Programs ◽  
Genetic Changes ◽  
Reintroduced Population ◽  
Source Populations ◽  
Conservation Breeding

The loss of genetic variation and genetic divergence from source populations are common problems for reintroductions that use captive animals or a small number of founders to establish a new population. This study evaluated the genetic changes occurring in a captive and a reintroduced population of the dibbler (Parantechinus apicalis) that were established from multiple source populations over a twelve-year period, using 21 microsatellite loci. While the levels of genetic variation within the captive and reintroduced populations were relatively stable, and did not differ significantly from the source populations, their effective population size reduced 10–16-fold over the duration of this study. Evidence of some loss of genetic variation in the reintroduced population coincided with genetic bottlenecks that occurred after the population had become established. Detectable changes in the genetic composition of both captive and reintroduced populations were associated with the origins of the individuals introduced to the population. We show that interbreeding between individuals from different source populations lowered the genetic relatedness among the offspring, but this was short-lived. Our study highlights the importance of sourcing founders from multiple locations in conservation breeding programs to avoid inbreeding and maximize allelic diversity. The manipulation of genetic composition in a captive or reintroduced population is possible with careful management of the origins and timings of founder releases.

Genetic Relatedness of Pecan Cultivars Determined by Using Random Amplified Polymorphic DNA (RAPD)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 493b-493
Author(s):  
Yongling Xiao ◽  
Dong Young Shin ◽  
Hazel Y. Wetzstein
Keyword(s):  
Genetic Variation ◽  
Genomic Dna ◽  
Genetic Relatedness ◽  
Random Amplified Polymorphic Dna ◽  
Breeding Programs ◽  
Parent Selection ◽  
Cultivar Classification

Although pecan (Carya illinoinensis) is an economically important nut and timber crop, little is known about the nature of genetic variation among pecan cultivars. In addition, the pedigree of many cultivars remains unknown or is questionable. In this study, the genomic DNA of 20 pecan cultivars were analyzed by RAPD, using 20 randomly selected oligoes as primers. Based on their genetic similarities derived from the RAPD data, the 20 pecan cultivars were classified into different groups. Pecan cultivars within the same group displayed very little genetic variation, whereas cultivars in different groups showed significant diversity. The putative origins for some pecan cultivars previously believed to have unknown pedigrees were also identified based on the RAPD data obtained. Results of this study provide information useful for pecan cultivar classification and parent selection in pecan breeding programs.

scholarly journals Modelling selection response in plant breeding programs using crop models as mechanistic gene-to-phenotype (CGM-G2P) multi-trait link functions

2020 ◽  
Author(s):  
M Cooper ◽  
O Powell ◽  
K P Voss-Fels ◽  
C D Messina ◽  
C Gho ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Plant Breeding ◽  
Complex Traits ◽  
Reference Population ◽  
Breeding Strategy ◽  
Breeding Value ◽  
Breeding Programs ◽  
Genetic Changes ◽  
Crop Models ◽  
Link Functions

Abstract Plant breeding programs are designed and operated over multiple cycles to systematically change the genetic makeup of plants to achieve improved trait performance for a Target Population of Environments (TPE). Within each cycle, selection applied to the standing genetic variation within a structured reference population of genotypes (RPG) is the primary mechanism by which breeding programs make the desired genetic changes. Selection operates to change the frequencies of the alleles of the genes controlling trait variation within the RPG. The structure of the RPG and the TPE has important implications for the design of optimal breeding strategies. The breeder’s equation, together with the quantitative genetic theory behind the equation, informs many of the principles for design of breeding programs. The breeder’s equation can take many forms depending on the details of the breeding strategy. Through the genetic changes achieved by selection, the cultivated varieties of crops (cultivars) are improved for use in agriculture. From a breeding perspective, selection for specific trait combinations requires a quantitative link between the effects of the alleles of the genes impacted by selection and the trait phenotypes of plants and their breeding value. This gene-to-phenotype link function provides the G2P map for one to many traits. For complex traits controlled by many genes, the infinitesimal model for trait genetic variation is the dominant G2P model of quantitative genetics. Here we consider motivations and potential benefits of using the hierarchical structure of crop models as CGM-G2P trait link functions in combination with the infinitesimal model for the design and optimisation of selection in breeding programs.

scholarly journals Mixing Genetically and Morphologically Distinct Populations in Translocations: Asymmetrical Introgression in A Newly Established Population of the Boodie (Bettongia lesueur)

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 729 ◽  
Author(s):  
Rujiporn Thavornkanlapachai ◽  
Harriet R. Mills ◽  
Kym Ottewell ◽  
Judy Dunlop ◽  
Colleen Sims ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Female Mate Choice ◽  
Effective Population ◽  
Island Populations ◽  
Loop Region ◽  
D Loop ◽  
Population Sizes ◽  
Ultimate Outcome ◽  
Different Populations ◽  
Source Populations

The use of multiple source populations provides a way to maximise genetic variation and reduce the impacts of inbreeding depression in newly established translocated populations. However, there is a risk that individuals from different source populations will not interbreed, leading to population structure and smaller effective population sizes than expected. Here, we investigate the genetic consequences of mixing two isolated, morphologically distinct island populations of boodies (Bettongia lesueur) in a translocation to mainland Australia over three generations. Using 18 microsatellite loci and the mitochondrial D-loop region, we monitored the released animals and their offspring between 2010 and 2013. Despite high levels of divergence between the two source populations (FST = 0.42 and ϕST = 0.72), there was clear evidence of interbreeding between animals from different populations. However, interbreeding was non-random, with a significant bias towards crosses between the genetically smaller-sized Barrow Island males and the larger-sized Dorre Island females. This pattern of introgression was opposite to the expectation that male–male competition or female mate choice would favour larger males. This study shows how mixing diverged populations can bolster genetic variation in newly established mammal populations, but the ultimate outcome can be difficult to predict, highlighting the need for continued genetic monitoring to assess the long-term impacts of admixture.

scholarly journals Modelling selection response in plant breeding programs using crop models as mechanistic gene-to-phenotype (CGM-G2P) multi-trait link functions

2020 ◽  
Author(s):  
M Cooper ◽  
O Powell ◽  
KP Voss-Fels ◽  
CD Messina ◽  
C Gho ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Plant Breeding ◽  
Complex Traits ◽  
Reference Population ◽  
Breeding Strategy ◽  
Breeding Value ◽  
Breeding Programs ◽  
Genetic Changes ◽  
Crop Models ◽  
Link Functions

AbstractPlant breeding programs are designed and operated over multiple cycles to systematically change the genetic makeup of plants to achieve improved trait performance for a Target Population of Environments (TPE). Within each cycle, selection applied to the standing genetic variation within a structured reference population of genotypes (RPG) is the primary mechanism by which breeding programs make the desired genetic changes. Selection operates to change the frequencies of the alleles of the genes controlling trait variation within the RPG. The structure of the RPG and the TPE has important implications for the design of optimal breeding strategies. The breeder’s equation, together with the quantitative genetic theory behind the equation, informs many of the principles for design of breeding programs. The breeder’s equation can take many forms depending on the details of the breeding strategy. Through the genetic changes achieved by selection, the cultivated varieties of crops (cultivars) are improved for use in agriculture. From a breeding perspective, selection for specific trait combinations requires a quantitative link between the effects of the alleles of the genes impacted by selection and the trait phenotypes of plants and their breeding value. This gene-to-phenotype link function provides the G2P map for one to many traits. For complex traits controlled by many genes, the infinitesimal model for trait genetic variation is the dominant G2P model of quantitative genetics. Here we consider motivations and potential benefits of using the hierarchical structure of crop models as CGM-G2P trait link functions in combination with the infinitesimal model for the design and optimisation of selection in breeding programs.

Genetic Relationships of Cory's Shearwater: Parentage, Mating Assortment, and Geographic Differentiation Revealed by DNA Fingerprinting

The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 651-662 ◽  
Author(s):  
Corinne Rabouam ◽  
Vincent Bretagnolle ◽  
Yves Bigot ◽  
Georges Periquet
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Dna Fingerprinting ◽  
Genetic Relatedness ◽  
Isolation By Distance ◽  
Genetic Relationships ◽  
Cory’S Shearwater ◽  
Genetic Structure Of Populations ◽  
The Social ◽  
Calonectris Diomedea

Abstract We used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.

scholarly journals Quantifying the prevalence of assortative mating in a human population

2019 ◽  
Author(s):  
Klaus Jaffe
Keyword(s):  
Assortative Mating ◽  
Genetic Relatedness ◽  
Random Mating ◽  
Human Populations ◽  
Genetic Composition ◽  
Genetic Studies ◽  
Maintenance Of Sex ◽  
Animal Populations ◽  
The Uk ◽  
First Time

AbstractFor the first time, empirical evidence allowed to construct the frequency distribution of a genetic relatedness index between the parents of about half a million individuals living in the UK. The results suggest that over 30% of the population is the product of parents mating assortatively. The rest is probably the offspring of parents matching the genetic composition of their partners randomly. High degrees of genetic relatedness between parents, i.e. extreme inbreeding, was rare. This result shows that assortative mating is likely to be highly prevalent in human populations. Thus, assuming only random mating among humans, as widely done in ecology and population genetic studies, is not an appropriate approximation to reality. The existence of assortative mating has to be accounted for. The results suggest the conclusion that both, assortative and random mating, are evolutionary stable strategies. This improved insight allows to better understand complex evolutionary phenomena, such as the emergence and maintenance of sex, the speed of adaptation, runaway adaptation, maintenance of cooperation, and many others in human and animal populations.

Quantifying genetic variation at the molecular level

2019 ◽  
pp. 34-66
Author(s):  
Asher D. Cutter
Keyword(s):  
Genetic Variation ◽  
Dna Sequences ◽  
Migration Rate ◽  
Population Genetic ◽  
Quantitative Methods ◽  
Molecular Level ◽  
Effective Population ◽  
Fundamental Properties ◽  
Site Frequency Spectrum ◽  
Population Genetic Variation

Chapter 3, “Quantifying genetic variation at the molecular level,” introduces quantitative methods for measuring variation directly in DNA sequences to help decipher fundamental properties of populations and what they can tell us about evolution. It provides an overview of the evolutionary factors that contribute to genetic variation, like mutational input, effective population size, genetic drift, migration rate, and models of migration. This chapter surveys the principal ways to measure and summarize polymorphisms within a single population and across multiple populations of a species, including heterozygosity, nucleotide polymorphism estimators of θ‎, the site frequency spectrum, and F ST, and by providing illustrative natural examples. Populations are where evolution starts, after mutations arise as the spark of population genetic variation, and Chapter 3 describes how to quantify the variation to connect observations to predictions about how much polymorphism there ought to be under different circumstances.

scholarly journals Deciphering genetic mate choice: Not so simple in group‐housed conservation breeding programs

2020 ◽  
Vol 13 (9) ◽  
pp. 2179-2189
Author(s):  
Katherine A. Farquharson ◽  
Carolyn J. Hogg ◽  
Katherine Belov ◽  
Catherine E. Grueber
Keyword(s):  
Mate Choice ◽  
Breeding Programs ◽  
Conservation Breeding
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