The hitch-hiking effect of a favourable gene

Smith, John Maynard; Haigh, John

doi:10.1017/s0016672300014634

Cited by 3,339 publications

(2,123 citation statements)

References 9 publications

Supporting

Mentioning

2,006

Contrasting

Unclassified

Order By: Relevance

“…LD, also called gametic phase disequilibrium, can be induced by selection, when one combination of alleles is favored over another. Under this positive selection the mating is non-random and the frequencies of advantageous alleles will increase (Falconer and Mackay, 1996), what is also known as 'the hitch-hiking effect of a favorable gene' (Smith and Haigh, 1974). The selective sweep can also occur with intermixture of populations with different gene frequencies.…”

Section: Relevance Of Linkage Disequilibrium and Relationship Levelmentioning

confidence: 99%

Review: Opportunities and challenges for small populations of dairy cattle in the era of genomics

Schöpke¹,

Swalve

2016

Animal

View full text Add to dashboard Cite

In modern dairy cattle breeding, genomic breeding programs have the potential to increase efficiency and genetic gain. At the same time, the requirements and the availability of genotypes and phenotypes present a challenge. The set-up of a large enough reference population for genomic prediction is problematic for numerically small breeds but also for hard to measure traits. The first part of this study is a review of the current literature on strategies to overcome the lack of reference data. One solution is the use of combined reference populations from different breeds, different countries, or different research populations. Results reveal that the level of relationship between the merged populations is the most important factor. Compiling closely related populations facilitates the accurate estimation of marker effects and thus results in high accuracies of genomic prediction. Consequently, mixed reference populations of the same breed, but from different countries are more promising than combining different breeds, especially if those are more distantly related. The use of female reference information has the potential to enlarge the reference population size. Including females is advisable for small populations and difficult traits, and maybe combined with genotyping females and imputing those that are un-genotyped.The efficient use of imputation for un-genotyped individuals requires a set of genotyped related animals and well-considered selection strategies which animals to choose for genotyping and phenotyping. Small populations have to find ways to derive additional advantages from the cost-intensive establishment of genomic breeding schemes. Possible solutions may be the use of genomic information for inbreeding control, parentage verification, within-herd selection, adjusted mating plans or conservation strategies.The second part of the paper deals with the issue of high-quality phenotypes against the background of new, difficult and hard to measure traits. The use of contracted herds for phenotyping is recommended, as additional traits, when compared to standard traits used in dairy cattle breeding can be measured at set moments in time. This can be undertaken even for the recording of health traits, thus resulting in complete contemporary groups for health traits. Future traits to be recorded and used in genomic breeding programs, at least partly will be traits for which traditional selection based on widespread phenotyping is not possible. Enabling phenotyping of sufficient numbers to enable genomic selection will rely on cooperation between scientists from different disciplines and may require multidisciplinary approaches.

show abstract

Section: Relevance Of Linkage Disequilibrium and Relationship Levelmentioning

confidence: 99%

Review: Opportunities and challenges for small populations of dairy cattle in the era of genomics

Schöpke¹,

Swalve

2016

Animal

View full text Add to dashboard Cite

show abstract

“…In this section, we follow the deterministic analysis of Maynard Smith & Haigh (1974). We assume that there is a haploid population and consider two diallelic loci with recombination rate c between them.…”

Section: Deterministic Analysis Of a Single Populationmentioning

confidence: 99%

“…We will characterize the effect of hitchhiking by deriving some approximate results for F ST . Following Maynard Smith & Haigh (1974) we write the variables in terms of conditional frequencies for the A allele and of the frequency of B. We define u " and u # to be the frequencies of A on B-bearing chromosomes in populations S " and S # and ν " and ν # be the frequencies of A on b-bearing chromosomes.…”

Section: Detailed Analysis Of Two Populationsmentioning

confidence: 99%

“…Genetic hitch-hiking is a term introduced by Maynard Smith & Haigh (1974) to describe the effect of a gene substitution at a selected locus on a closely linked neutral locus. Maynard Smith & Haigh found that heterozygosity would be reduced significantly at the neutral locus provided that the selection coefficient, s, is larger than the recombination rate, c, between the selected and neutral loci.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Genetic hitch-hiking in a subdivided population

1998

View full text Add to dashboard Cite

SummaryThe problem of genetic hitch-hiking in a geographically subdivided population is analysed under the assumption that migration rates among populations are relatively small compared with the selection coefficient for a newly arising advantageous allele. The approximate method used in the paper is valid when the number of emigrants per generation (Nm) is less than one. The approximate analysis shows that hitch-hiking can result in substantial differences among populations in the frequencies of neutral alleles closely linked to the advantageous allele. Thus, in cases for which genetic hitch-hiking is thought to be responsible for low levels of genetic variability in regions of the genome with restricted crossing over, it might be possible to find confirmatory evidence for that hypothesis by finding unusual patterns of geographic differentiation in the same regions of the genome.

show abstract

“…Conversely, under positive selection, beneficial recessive mutations should become fixed at a higher rate on the X chromosome than on any autosome, again because of hemizygous expression of X chromosomes in males. Fixation of beneficial mutations is expected to lead to a loss of neutral variability in linked loci, owing to genetic hitchhiking, thus higher rates of fixation on the X caused by positive selection would lead to lower neutral variability on the X than the autosomes (Maynard Smith & Haigh, 1974;Charlesworth et al, 1987). Thus, the two forms of selection make contrasting predictions for levels of neutral variability for X-linked versus autosomal loci.…”

Section: Introductionmentioning

confidence: 99%

Microsatellite variation among divergent populations of stalk-eyed flies, genus Cyrtodiopsis

et al. 2004

View full text Add to dashboard Cite

SummaryMicrosatellite primers are often developed in one species and used to assess neutral variability in related species. Such analyses may be confounded by ascertainment bias (i.e. a decline in amplification success and allelic variability with increasing genetic distance from the source of the microsatellites). In addition, other factors, such as the size of the microsatellite, whether it consists of perfect or interrupted tandem repeats, and whether it is autosomal or X-linked, can affect variation. To test the relative importance of these factors on microsatellite variation, we examine patterns of amplification and allelic diversity in 52 microsatellite loci amplified from five individuals in each of six populations of Cyrtodiopsis stalk-eyed flies that range from 2 . 2 % to 11 . 2% mitochondrial DNA sequence divergence from the population used for microsatellite development. We find that amplification success and most measures of allelic diversity declined with genetic distance from the source population, in some cases an order of magnitude faster than in birds or mammals. The median and range of the repeat array length did not decline with genetic distance. In addition, for loci on the X chromosome, we find evidence of lower observed heterozygosity compared with loci on autosomes. The differences in variability between X-linked and autosomal loci are not adequately explained by differences in effective population sizes of the chromosomes. We suggest, instead, that periodic selection events associated with X-chromosome meiotic drive, which is present in many of these populations, reduces X-linked variation.

show abstract

The hitch-hiking effect of a favourable gene

Cited by 3,339 publications

References 9 publications

Review: Opportunities and challenges for small populations of dairy cattle in the era of genomics

Review: Opportunities and challenges for small populations of dairy cattle in the era of genomics

Genetic hitch-hiking in a subdivided population

Microsatellite variation among divergent populations of stalk-eyed flies, genus Cyrtodiopsis

Contact Info

Product

Resources

About