Genetic Diversity and Population Assessment of Musa L. (Musaceae) Employing CDDP Markers

Sixty-six accessions of Musa genus with different genomic groups that consisted of wild relatives and cultivated lines were obtained from the International Transit Center, Belgium, for DNA extraction using Cetyl trimethylammonium bromide method, followed by amplification with Conserved DNA-derived Polymorphism (CDDP) markers for genetic diversity and population assessment. A total of 421 alleles with major allele frequency of 2.051 were detected from the reproducible markers. High genetic diversity (GD, 11.093) and polymorphic information content (0.918) were revealed. The number of polymorphic loci and percentage of polymorphic loci ranged from 59 to 66 and 89.34 to 100, respectively. Using the potential genetic indicators including effective number of alleles, Nei’s genetic diversity, and Shannon’s information index, the AS genomic group was identified to have the highest GD, while the AAA accessions had the lowest GD indices. The GD parameters identified in the accessions were ranked as AS > AAB > AAAA > AA > ABB > wild diploidy > BB > AB > AAA from high to low based on polymorphic loci of the markers. Total intraspecific GD, interspecific GD, and estimate gene flow identified were 0.433, 0.404, and 7.113, respectively. The coefficient of gene differentiation of 0.066 was obtained, indicating 6.57% among the population and 93.43% within the population. Dendrogram analysis produced nine major groups with subgroups at similarity index of 0.814. These CDDP functional gene-based markers were informative and very efficient in resolving GD, and population indices among the banana and plantain accessions of different genomes. The identified CDDP markers might serve as potential tools for selecting suitable training populations for breeding and conservation of Musa species.

Gene flow in three broiler chicken populations in Abeokuta using jackknife procedure

Jackknife procedure (JP) is a less biased and fascinating method of obtaining gene slow among populations. The purpose of this study was to use JP to eliminate bias associated with indirect estimators of gene slow, with microsatellite markers, it has been possible to estimate gene flow (Nm) in natural populations. To quantify Nm, in chicken populations, we used five polymorphic microsatellite markers with 115 genomic deoxyribonucleic acid (DNA) obtained from (dihybrid (DH = 37), trihybrid (TH = 32) and Anak White (AW = 46) broiler chicken populations, respectively. Through polymerase chain reaction, we amplified DNA from the broiler chicken populations, subjected amplicons to electrophoresis, fragment sizes determined and analysed across populations considering selected markers through which standardized genetic variance among sub-populations in total sample depicted as (FST) was obtained per marker for chicken population pairs. Its average across markers/population pairs was used to infer Nm, in the chicken population pairs. We used JP which is a mathematical approach that utilizes mean FST, across markers to obtain Nm in the chicken population pairs. Gene flow based on JP in chicken population pairs designated as (Nm)JP were 5.4267 (DH vs. TH), 7.0127 (TH vs. AW) and 11.7405 (DH vs. AW) and among chicken populations, (Nm)JP was 7.1969. Considering these estimates, we concluded that there was gene flow among the three broiler chicken populations examined in Abeokuta, Nigeria.

Gene flow in three broiler chicken populations in Abeokuta using jackknife procedure

Jackknife procedure (JP) is a less biased and fascinating method of obtaining gene flow among populations. The purpose of this study was to use JP to eliminate bias associated with indirect estimators of gene flow. With microsatellite markers, it has been possible to estimate gene flow (Nmo ) in natural populations. To quantify Nmo in chicken populations, we used five polymorphic microsatellite markers with 115 genomic deoxyribonucleic acid (DNA) obtained from (dihybrid (DH = 37), trihybrid (TH = 32) and Anak White (AW = 46) broiler chicken populations, respectively. Through polymerase chain reaction, we amplified DNA from the broiler chicken populations, subjected amplicons to electrophoresis, fragment sizes determined and analysed across populations considering selected markers through which standardized genetic variance among sub-populations in total sample depicted as (F)ST was obtained per marker for chicken population pairs. Its average across markers/population pairs was used to infer Nmo in the chicken population pairs. We used JP which is a mathematical approach that utilizes mean FST across markers to obtain Nmo in the chicken population pairs. Gene flow based on JP in chicken population pairs designated as (Nm)JP were 5.4267 (DH vs. TH), 7.0127 (TH vs. AW) and 11.7405 (DH vs. AW) and among chicken populations, (Nm)JP was 7.1969. Considering these estimates, we concluded that there was JP gene flow among the three broiler chicken populations examined in Abeokuta, Nigeria.

Population history and the differential consequences of inbreeding and outcrossing in a plant metapoplation

ABSTRACTThe phenotypic consequences of inbreeding typically result in a fitness decline proportional to the increase in the inbreeding coefficient, F. This basic assumption of a predictable, inverse relationship between fitness and F has been questioned by a number of empirical studies. We explored the relationship between population history and inbreeding in a metapopulation of the plant Silene latifolia, for which long-term data are available for the historical size and spatial distribution of hundreds of local demes. We used a population genetic analysis to estimate gene flow and bi-parental inbreeding (FIS) in demes with different histories of spatial isolation. A controlled crossing experiment examined whether the effect of inbreeding and outcrossing on fitness-related traits varied with different histories of population size and isolation. Historically isolated demes experienced less gene flow and an increase in FIS, as well as significant inbreeding advantage and outbreeding depression for traits expressed early in life. The causes of variation in the F-fitness relationship among populations will include variance in the distribution of deleterious recessive alleles driven by aspects of population history, including population size, founder effects, gene flow, bi-parental inbreeding, and opportunities for the purging of genetic load. Our findings show that isolation and historical variation in population size likely contribute substantial variation in past inbreeding and the consequences of future inbreeding across the metapopulation.

Gene flow despite complex Robertsonian fusions among rock-wallaby ( Petrogale ) species

Complex Robertsonian rearrangements, with shared arms in different fusions, are expected to prevent gene flow between hybrids through missegregation during meiosis. Here, we estimate gene flow between recently diverged and chromosomally diverse rock-wallabies ( Petrogale ) to test for this form of chromosomal speciation. Contrary to expectations, we observe relatively high admixture among species with complex fusions. Our results reinforce the need to consider alternative roles of chromosome change, together with genic divergence, in driving speciation.

Reproduction and dispersal at vents and cold seeps

Reproductive cycles are determined from samples taken at regular intervals over a period of time related to the assumed periodicity of the breeding cycle. Fiscal, ship time and sampling constraints have made this almost impossible at deep-sea vents and seeps, but there is an accumulating mass of data that cast light on these processes. It is becoming apparent that most reproductive processes are phylogenetically conservative, even in extreme vent and seep habitats. Reproductive patterns of species occurring at vents and seeps are not dissimilar to those of species from the same phyla found in non-chemosynthetic environments. The demographic structure of most vent and seep animals is undescribed and the maximum ages and growth rates are not known. We know little about how the gametogenic cycle is initiated, though there is a growing body of data on the size at first reproduction. Gametogenic biology has been described from seasonal samples for only one organism from vent/seep environments. For other species, the pattern of gametogenesis has been described from serendipitous samples that allow determination of reproductive effort, but such samples reveal little about energy partitioning during the gametogenic process. Some notable adaptations have been described in mature gametes, including modified sperm. Spawning has been observed for a number of species both in situ and in vitro. Knowledge of the larvae of vent/seep organisms has been derived from laboratory fertilizations, from field collections over vent and seep areas and, for molluscs, from protoconch or prodissoconch size and shape. Larval dispersal has been perhaps the most intractable aspect of reproduction. Because the length of larval life is known for only a single seep organism and no vent organism, we cannot infer dispersal distance from a knowledge of current velocities. Modelling has been used to assess the maximum larval distance that allows effective migration between vent sectors. An indirect approach has been to estimate gene flow within, and between, vent sites using DNA sequencing and electrophoretic techniques. Although data are still equivocal, there are indications of considerable mixing among populations within and between vent sectors of the same ridge. Our knowledge of reproductive biology in vent and seep organisms remains fragmentary, but with molecular and biochemical techniques, emerging larval culture techniques, and increased sampling effort, the pieces of the jigsaw will eventually form an overall picture.