So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Community-Based Participatory Researchに関する文献レビュー (焦点 Community-Based Participatory Research--患者・家族・市民とともに創る研究)

Characterization of indigenous goats types of Eritrea, Nothern and Western Ethiopia.

A total of 3460 lactation records that represented 1059 dairy Holstein-Friesian cows were used in the present study that aimed to estimate genetic parameters such as heritability, genetic correlations, phenotypic correlations and genetic trends for some productive and reproductive traits. Studied traits were total milk yield, days in milk, fat %, protein %, dry period, age at first calving, number of services per conception, days open and calving interval. Data were collected from Egyptian Copenhagen Company in Alexandria-Cairo desert road for cows calved from 1998 to 2010. Least square analysis of mixed sire model was used in analysis using Harvey (1990) program. Heritability estimates were high for all traits and very high for fat and protein % that exceeded 0.83 in two lactations. Genetic correlations were higher than phenotypic correlations and were high especially among production traits. Regression coefficients of genetic trends were positive for all studied traits except for days in milk and days open (in second lactation) and age at first calving. Generally, the current results showed genetic improvement of most of traits that reflect the efficiency of selection programs.

https://scvmj.journals.ekb.eg/article_78285_74f0a170a39b91550c5a8c4581c18137.pdf

Estimation of heritabilities, genetic correlations, phenotypic correlations and genetic trends for production and reproduction traits of Holstein-Friesian dairy cattle using sire model

Ethiopia is endowed with different Indigenous cattle genetic resources with millions of people directly depending on them. However, despite the potentials of these diversified genetic resources, the huge loss of cattle genetic diversity is becoming a prominent challenge these days. The aim of this review is to show the current status and performance of some selected indigenous cattle breeds of Ethiopia for better understanding of the situation of these breeds for the collective efforts towards conserving and improving the breeds. Based on the review, there are persuasive evidences on the critical situation of the selected indigenous cattle breeds. The facts and figures of the past and current situation of the selected indigenous cattle of Ethiopia showed that the situation of these breeds is very critical. This situation therefore demands the need to devise strategies to conserve and improve the cattle breeds based on the challenges that threatens them. Use of new biological and information technologies is also imperative to facilitate the genetic restoration process. Besides, use of new biological and information technologies which can enhance the conservation and improvement program are crucial. Various ongoing development interventions like Artificial Insemination and introduction of genotypes into new environments that are exacerbating threat of the breeds should totally be avoided by revising and designing sound approaches for cattle Conservation and improvement programs. Strict regulations and by laws should also be in place for illegal movement of breeding cattle to the neighboring countries.

A review on Indigenous cattle genetic resources in Ethiopia: adaptation, status and survival.

A total of 1979 lactation records from 550 selected crossbred dairy cows that born between 1974 and 2005 were used to estimate annual genetic and environmental trends in milk production and reproduction traits at Holetta Agricultural Research Center, Ethiopia. Annual genetic and environmental trends were estimated by regressing BLUP estimated breeding value on year of birth. Variance components and genetic parameters were estimated using univariate analysis of individual animal model based on restricted maximum likelihood procedures. Annual genetic trends were -3.384 days, -8.00 kg and -5.96 kg, -0.26 months, -0.29 months and -0.88 days, for lactation length (LL), lactation milk yield (LMY), adjusted 305 milk yield (305-days MY), age at puberty (APU), age at first calving (AFC) and calving interval (CI), respectively. Environmental trends for LMY was positive (6.717 kg) and was in the desired direction. Heritability estimates were 0.14, 0.44, 0.39, 0.38, 0.40 and 0.17 for LL, LMY, 305-d MY, APU, AFC and CI, respectively. Negative genetic trends in all milk production traits reflect ineffective selection program and/or lack of using sires that have positive breeding values. The result from the environmental trends shows substantial improvement in the management practices over time. Contrasting directions in genetic and environmental trends reflect ineffective breeding objectives. This warrants reconsideration of the existing breeding program in the country.

	 

	Key words: Genetic trends, environmental trends, genetic parameters, breeding objectives, variance components.

https://www.africaneditors.org/journal/JCAB/full-text-pdf/84812-120692

Genetic and environmental trends in the long-term dairy cattle genetic improvement programmes in the central tropical highlands of Ethiopia.

Longevity traits, lifetime milk and calf productivities are one of the primary interests of dairy cattle producers. We used lifetime data of 523 crossbred dairy cows that born between 1980 and 2003 in the central tropical highlands of Ethiopia with the purpose to evaluate longevity traits and associated lifetime milk and calf productivity. Based on the type of sires used and level of exotic gene inheritances, the crossbred dairy cows were classified in to six genetic groups. These include F1 Friesian x Boran (F1 FxBo), F1 Jersey x Boran (F1 JxBo), F2 Friesian x Boran (F2 FxBo), F2 Jersey x Boran (F2 JxBo) and 75% Friesian and Jersey inheritances. A Generalized Linear Model in the statistical analysis system (SAS, 2004) was used to analyze the data. The overall least squares means ± s. e. for total life (TL), herd life (HL), productive life (PL), lifetime milk yield (LTMY) and lifetime calf crop production were 4036 ± 126.3 days, 2675.74 ± 201.7 days, 1951.00 ± 173.8 days, 10460.6 ± 1117.4 L and 5.70 ± 0.2 calves, respectively. The overall least squares means ± s. e. for lifetime milk yield per day of total life (LTMY/TL), lifetime milk yield per day of herd life (LTMY/HL) and lifetime milk yield per day of productive life (LTMY/PL) were 2.56 ± 0.2, 3.97 ± 0.3 and 5.26 ± 0.3 L, respectively. In conclusion, first generation crosses of all types, particularly those sired by Jersey semen were superior in all the lifetime performance traits considered in this study while second generation (F2) crosses were inferior in all the lifetime productivity indicators.

	Key words: Herd life, lifetime milk yield, longevity, productive life.

/pdf/analysis-of-longevity-traits-and-lifetime-productivity-of-16j4h8jwpi.pdf

Analysis of longevity traits and lifetime productivity of crossbred dairy cows in the Tropical Highlands of Ethiopia

The study was undertaken in bale zone to assess farmer’s selective breeding objectives, trait preferences, selection criteria and breeding system October 2012 to November 2013. A purposive and multistage sampling technique was applied for selection of 3 district and 9 kebeles. Then 360 households were selected by using simple random sampling techniques after the list of pastoralist having goats was identified. Statistical analysis system version 9.1 was used for analysis of data. Indices, effective population size and rate of inbreeding were calculated on average each respondent holds about 14 goats. Milk production is the main reason of goat keeping in the study area. Appearance is the first rank as selection criteria for male and female in all studies area. About 47.8% of the respondents have their own buck. The main use of breeding buck in the study area was for mating purpose (76.2%). Mean estimate of effective population size and mean rate of inbreeding was 2.43 and 0.21, respectively when a household flock is herded alone and under random mating. Therefore, any breed improvement strategies that are intended to be implemented in the study area and else- where should consider the traditional breeding practices and breeding objectives of the community. Int. J. Agril. Res. Innov. & Tech. 5 (2): 7-15, December, 2015

/pdf/breeding-objectives-selection-criteria-and-breeding-system-30hysrxud6.pdf

Breeding objectives, selection criteria and breeding system of indigenous goat types in bale zone, oromia, Ethiopia

Cattle breeding strategies for sustainable genetic improvement in Ethiopia

Matrilineal genetic diversity and relationship were investigated among eight morphologically identified native Ethiopian horse populations using polymorphisms in 46 mtDNA D-loop sequences (454 base pairs). The horse populations identified were Abyssinian, Bale, Borana, Horro, Kafa, Kundido feral horses, Ogaden and Selale. Mitochondrial DNA D-loop sequences were characterized by 15 variable sites that defined five different haplotypes. All genetic diversity estimates, including Reynolds’ linearized genetic distance, genetic differentiation (FST) and nucleotide sequence divergence (DA), revealed a low genetic differentiation in native Ethiopian horse populations. However, Kundido feral and Borana domestic horses were slightly diverged from the rest of the Ethiopian horse populations. We also tried to shed some light on the matrilineal genetic root of native Ethiopian horses from a network constructed by combining newly generated haplotypes and reference haplotypes deposited in the GenBank for Eurasian type Turkish Anatolian horses that were used as a genetic conduit between Eurasian and African horse populations. Ninety-two haplotypes were generated from the combined Ethio-Eurasian mtDNA D-loop sequences. A network reconstructed from the combined haplotypes using Median-Joining algorithm showed that haplotypes generated from native Ethiopian horses formed separate clusters. The present result encourages further investigation of the genetic origin of native African horses by retrieving additional mtDNA sequences deposited in the GenBank for African and Eurasian type horses.

https://www.mdpi.com/2073-4425/12/2/155/pdf

Kefena Effa

Papers

Genetic and environmental trends in the long-term dairy cattle genetic improvement programmes in the central tropical highlands of Ethiopia.

Analysis of longevity traits and lifetime productivity of crossbred dairy cows in the Tropical Highlands of Ethiopia

Breeding objectives, selection criteria and breeding system of indigenous goat types in bale zone, oromia, Ethiopia

Cattle breeding strategies for sustainable genetic improvement in Ethiopia

Genetic Diversities and Historical Dynamics of Native Ethiopian Horse Populations (Equus caballus) Inferred from Mitochondrial DNA Polymorphisms.