1 00:00:00,000 --> 00:00:08,000 My name is Ewa Wójcik, I am an employee of the Institute of Animal Production and Fisheries at the Faculty of Agricultural Sciences of the University of Siedlce. 2 00:00:08,000 --> 00:00:14,000 I would like to present the topic of genetic traits in animal production. 3 00:00:14,000 --> 00:00:20,000 Production characteristics are those characteristics that have enormous economic significance. 4 00:00:20,000 --> 00:00:24,000 Mainly belong to the category of quantitative characteristics. 5 00:00:24,000 --> 00:00:30,000 The inheritance mechanism of these traits is very difficult and complex to explain. 6 00:00:30,000 --> 00:00:36,000 The variability of these traits also depends on environmental influences. 7 00:00:36,000 --> 00:00:41,000 Quantitative traits are controlled by multiple genes at different loci. 8 00:00:41,000 --> 00:00:48,000 They are also known as polygenes, polymeric genes, cumulative genes, or additive genes. 9 00:00:48,000 --> 00:00:54,000 Polygenes interact to create a trait, and the effects of individual polygenes. 10 00:00:54,000 --> 00:00:58,000 They add up and determine the intensity of the trait. 11 00:00:58,000 --> 00:01:03,000 The number of polygenes controlling quantitative traits is unknown. 12 00:01:03,000 --> 00:01:09,000 Each of the polygenes has two alleles with intermediate inheritance. 13 00:01:09,000 --> 00:01:14,000 One of the alleles always has a positive character, while the other is neutral. 14 00:01:14,000 --> 00:01:18,000 Positive allele effects from individual loci are equal. 15 00:01:18,000 --> 00:01:23,000 The effects of these genes add up in shaping the phenotype. 16 00:01:23,000 --> 00:01:30,000 Examples of such characteristics may include height, weight, growth rate, performance, circumference, 17 00:01:30,000 --> 00:01:33,000 surface whether it's parts of the body or the whole body. 18 00:01:33,000 --> 00:01:39,000 These features are always expressed using units of measurement such as meter, square meter. 19 00:01:39,000 --> 00:01:43,000 cubic meter, kilogram or other units of measurement. 20 00:01:44,000 --> 00:01:50,000 Phenotypic expression of quantitative traits is highly dependent on environmental factors. 21 00:01:50,000 --> 00:01:55,000 They can enhance or weaken the action of polygenes. 22 00:01:55,000 --> 00:02:02,000 With the appropriate genotype and environmental influences shaping and influencing the phenotype, 23 00:02:02,000 --> 00:02:07,000 we can obtain a higher phenotypic value from a given animal, 24 00:02:07,000 --> 00:02:12,000 providing the animal with appropriate living conditions. 25 00:02:12,000 --> 00:02:19,000 Another environmental factor is the maternal effect and although the number of chromosomes, 26 00:02:19,000 --> 00:02:24,000 which an individual receives from their parents is the same, 27 00:02:24,000 --> 00:02:30,000 The influence of the mother on offspring is greater and stems from three basic sources. 28 00:02:30,000 --> 00:02:35,000 First of all, from the genetic background, i.e. extranuclear mitochondrial inheritance, 29 00:02:35,000 --> 00:02:41,000 influence of the mother's environment during the prenatal period, also known as the prenatal effect 30 00:02:41,000 --> 00:02:47,000 The postnatal environmental influences on the mother after birth, or the postnatal effect. 31 00:02:47,000 --> 00:02:52,000 These features may have a continuous nature, with the value of the feature in the population. 32 00:02:52,000 --> 00:02:57,000 It can take any value between maximum and minimum. 33 00:02:57,000 --> 00:03:03,000 The value of this trait in an individual can circulate anywhere within this range. 34 00:03:03,000 --> 00:03:08,000 The number of possible phenotypes in practice is unlimited. 35 00:03:08,000 --> 00:03:13,000 And an example of such a trait could be milk production. 36 00:03:13,000 --> 00:03:17,000 The second category of features is jump features. 37 00:03:17,000 --> 00:03:22,000 The values of these features are expressed by a number of specified units. 38 00:03:22,000 --> 00:03:27,000 In the population, the trait ranges from minimum to maximum values. 39 00:03:27,000 --> 00:03:32,000 The value of features for a specific individual must be expressed in whole number units. 40 00:03:32,000 --> 00:03:39,000 An example of a jump trait could be the number of eggs laid or the number of offspring in a litter. 41 00:03:39,000 --> 00:03:48,000 The next threshold traits are conditioned by the influence of multiple genes and environmental factors. 42 00:03:48,000 --> 00:03:54,000 Usually they exhibit two or very few phenotypic forms. 43 00:03:54,000 --> 00:03:59,000 Genetic variability is heritable, while phenotypic variability is qualitative in nature. 44 00:03:59,000 --> 00:04:05,000 very often binary. An example of such features is disease resistance. 45 00:04:05,000 --> 00:04:11,000 This trait manifests either through experience or death, with no in-between states. 46 00:04:11,000 --> 00:04:17,000 Another example is the litter size in large animals, which typically give birth to one offspring. 47 00:04:17,000 --> 00:04:21,000 but sometimes they can give birth to twins or triplets. 48 00:04:21,000 --> 00:04:27,000 The property of a threshold trait is the so-called threshold to which the genes referred to. 49 00:04:27,000 --> 00:04:33,000 which crossing results in an elemental phenotypic change. 50 00:04:33,000 --> 00:04:39,000 The distribution of a characteristic is a parameter that describes the population and informs us, 51 00:04:39,000 --> 00:04:45,000 What proportion of individuals in a population exhibit each possible value of a trait, 52 00:04:45,000 --> 00:04:51,000 Each possible phenotype. The description of the distribution of the trait depends on the number of phenotypic classes. 53 00:04:52,000 --> 00:04:57,000 The greater the number of phenotypes, the more difficult it is to describe the distribution of a trait. 54 00:04:57,000 --> 00:05:03,000 We distinguish between continuous, jump, and threshold distributions. 55 00:05:03,000 --> 00:05:09,000 Distribution of phenotypes in case of continuous distribution, most of these quantitative traits. 56 00:05:09,000 --> 00:05:13,000 It corresponds to the bell curve, or normal distribution curve. 57 00:05:13,000 --> 00:05:17,000 This is the distribution that most individuals obtain. 58 00:05:17,000 --> 00:05:21,000 characterized by values of the measured feature to the average, 59 00:05:21,000 --> 00:05:26,000 It takes the least extreme values, above and below average. 60 00:05:26,000 --> 00:05:33,000 The normal distribution is symmetric, with the axis of symmetry passing through the mean. 61 00:05:33,000 --> 00:05:39,000 The parameters for the normal distribution are the mean and standard deviation. 62 00:05:39,000 --> 00:05:44,000 Jumping distribution describes the abundance of different phenotypic classes. 63 00:05:44,000 --> 00:05:46,000 how many of them we have. 64 00:05:46,000 --> 00:05:50,000 Progressive distribution, in turn, describes the number of each. 65 00:05:50,000 --> 00:05:53,000 Most commonly two categories of phenotypic classes. 66 00:05:53,000 --> 00:05:58,000 Category A, Category B. 67 00:05:58,000 --> 00:06:08,000 The environment has a huge impact on the intensity of a given phenotypic trait, enhancing it to varying degrees. 68 00:06:08,000 --> 00:06:11,000 Increasing or decreasing values. 69 00:06:12,000 --> 00:06:18,000 The increased variability of the trait is a result of the appearance of environmental effects. 70 00:06:18,000 --> 00:06:22,000 Difficulty in determining the genotypic value of individuals. 71 00:06:22,000 --> 00:06:28,000 Then the curve is more flattened compared to the Gaussian curve. 72 00:06:30,000 --> 00:06:34,000 The phenomenon of transgression is associated with quantitative features. 73 00:06:34,000 --> 00:06:39,000 Livestock animals are heterozygous for a significant number of genes. 74 00:06:40,000 --> 00:06:45,000 offspring may exhibit higher trait values due to crossing such individuals 75 00:06:45,000 --> 00:06:48,000 lower than their parents. 76 00:06:48,000 --> 00:06:54,000 This phenomenon is called transgression and is widely used in breeding work. 77 00:06:55,000 --> 00:07:00,000 Genes with large effects are also associated with quantitative traits. 78 00:07:00,000 --> 00:07:04,000 so-called QTLs, Quantitype Atriot Locus. 79 00:07:04,000 --> 00:07:10,000 The graphical distribution of phenotypes for some traits significantly deviates from the normal distribution curve. 80 00:07:10,000 --> 00:07:17,000 This is the result of inheritance, when polygenic genes are also at play. 81 00:07:17,000 --> 00:07:21,000 Genes with a large effect, known as QE genes. 82 00:07:21,000 --> 00:07:27,000 He is identified as a homozygous recessive when the trait values differ. 83 00:07:27,000 --> 00:07:31,000 exceed at least one standard deviation. 84 00:07:31,000 --> 00:07:37,000 Perhaps then the normal distribution can be skewed to the left or right. 85 00:07:39,000 --> 00:07:46,000 Examples of genes with large effect on various production traits in cattle 86 00:07:46,000 --> 00:07:53,000 For example, there is the growth hormone GH which affects higher milk production. 87 00:07:53,000 --> 00:07:56,000 compared to homozygous dominant individuals. 88 00:07:57,000 --> 00:08:03,000 It also affects meat utility traits, growth rate, and carcass composition. 89 00:08:03,000 --> 00:08:08,000 together with the insulin-like growth factor gene. 90 00:08:08,000 --> 00:08:13,000 It also affects the length and circumference of the chest, the aging process. 91 00:08:13,000 --> 00:08:17,000 reproduction and the immune response of the organism. 92 00:08:17,000 --> 00:08:23,000 Gen ten odpowiada za niektóre zaburzenia rozwojowe, tak jak karłowatość czy akromegalia. 93 00:08:23,000 --> 00:08:25,000 also identified in poultry. 94 00:08:27,000 --> 00:08:33,000 The next major genes found in cattle are milk protein genes. 95 00:08:33,000 --> 00:08:38,000 It contains kappa casein. It is related to the properties of milk functionality. 96 00:08:38,000 --> 00:08:43,000 such as milk yield, protein yield, fat yield. 97 00:08:43,000 --> 00:08:49,000 Milk with kappa casein B gene has higher protein content and better suitability. 98 00:08:49,000 --> 00:08:55,000 to cheese production compared to milk with the kappa casein variant A. 99 00:08:55,000 --> 00:09:02,000 Another gene, the beta-lactoglobulin gene, affects milk yield and its components. 100 00:09:02,000 --> 00:09:08,000 Milk containing beta-lactoglobulin B differs from milk with the A variant. 101 00:09:08,000 --> 00:09:15,000 higher dry matter content, fat and casein content, and better technological suitability. 102 00:09:15,000 --> 00:09:22,000 Another gene, the diacylglycerol acetyltransferase gene, affects milk yield. 103 00:09:22,000 --> 00:09:28,000 protein and fat in milk and intramuscular fat content. 104 00:09:28,000 --> 00:09:34,000 Muscle hypertrophy, in turn, increases the lean meat content in the carcass. 105 00:09:34,000 --> 00:09:40,000 Better dietary properties due to reduced fat and connective tissue. 106 00:09:40,000 --> 00:09:45,000 This trait is highly preferred by breeders of both purebred cattle breeds. 107 00:09:45,000 --> 00:09:49,000 From Belgian Blue cattle as well as their crossbreeds. 108 00:09:49,000 --> 00:09:56,000 Unfortunately, genetics also have a negative impact, for example delaying the onset of sexual maturity in both males and females. 109 00:09:56,000 --> 00:10:04,000 It affects reduced fertility in male goats, lower concentrations of sex hormones in the blood serum. 110 00:10:04,000 --> 00:10:11,000 smaller circumference and mass of the nucleus. In cows, pregnancy is prolonged and fetal mass is increased. 111 00:10:11,000 --> 00:10:15,000 which causes many problems during natural childbirth. 112 00:10:16,000 --> 00:10:24,000 In pig, the main gene for malignant hyperthermia is the ryanodine receptor I gene. 113 00:10:24,000 --> 00:10:29,000 It increases pigs' susceptibility to stress by inducing the so-called PSS syndrome. 114 00:10:29,000 --> 00:10:37,000 It may be caused by stress on transportation, thermal conditions, chemical factors. 115 00:10:37,000 --> 00:10:43,000 As a result of these stress myopathies, unfavorable physicochemical changes occur in the body. 116 00:10:43,000 --> 00:10:50,000 Deterioration in meat quality, discoloration, unpleasant odor, excessive softness, and watery texture. 117 00:10:50,000 --> 00:10:56,000 Gen ten jednocześnie dodatnio wpływa na niektóre cechy związane z użytkowością mięsną np. 118 00:10:56,000 --> 00:11:03,000 meat content in the loin eye surface, which is most beneficial in heterozygotes 119 00:11:03,000 --> 00:11:10,000 being carriers of this mutated allele. Such animals are good material for fattening. 120 00:11:10,000 --> 00:11:15,000 Gentian also occurs in other species such as cattle, horses, and humans. 121 00:11:17,000 --> 00:11:26,000 Sour meat gene, gamma protein kinase C subunit gene 122 00:11:26,000 --> 00:11:33,000 Mutant allele carriers have twice as much myogenin content in their muscles, especially in the hamstrings. 123 00:11:33,000 --> 00:11:40,000 Another main gene, insulin-like growth factor 2, influences meat quality traits. 124 00:11:40,000 --> 00:11:45,000 increased muscle mass, decreased back fat content. 125 00:11:45,000 --> 00:11:52,000 Another major gene, a gene influencing litter size, naturally affects fertility and litter size. 126 00:11:52,000 --> 00:12:00,000 Litters with two copies of this gene in their genotype produce 1 to 1.4% more offspring. 127 00:12:00,000 --> 00:12:05,000 compared to non-carrier dams. 128 00:12:05,000 --> 00:12:15,000 In sheep, the main gene is the muscle hypertrophy gene, which causes a 32% increase in muscle mass. 129 00:12:15,000 --> 00:12:22,000 Reduced fat content by about 8% and improved feed efficiency. 130 00:12:22,000 --> 00:12:27,000 Another high-fertility gene, causing a high degree of ovulation in sows, 131 00:12:27,000 --> 00:12:32,000 affects the development of Graafian follicles and corpus luteum, decreased secretion 132 00:12:32,000 --> 00:12:39,000 inhibitors of hormones acting on gonadotropins and increasing ovulation, 133 00:12:39,000 --> 00:12:45,000 increasing the fertility by about one lamb. 134 00:12:45,000 --> 00:12:50,000 Knowledge of genetic variability is particularly important in breeding work. 135 00:12:50,000 --> 00:12:53,000 in the phenotypic variability of a given quantitative trait. 136 00:12:53,000 --> 00:12:58,000 The estimation of this proportion uses heritability, which we can express as 137 00:12:58,000 --> 00:13:04,000 Using the formula where heritability equals the ratio of genetic variance to total phenotypic variance. 138 00:13:04,000 --> 00:13:07,000 from genetic to phenotypic variability. 139 00:13:07,000 --> 00:13:12,000 Inheritance determines the strength of the relationship between an animal's phenotype. 140 00:13:12,000 --> 00:13:17,000 The genetic value of individuals for their offspring, i.e. breeding value. 141 00:13:17,000 --> 00:13:22,000 If a trait is highly heritable, then the animal's phenotype is very good. 142 00:13:22,000 --> 00:13:25,000 source of information about his genes. 143 00:13:25,000 --> 00:13:30,000 When heritability is high, greater phenotypic similarity is observed. 144 00:13:30,000 --> 00:13:35,000 between closely related individuals, for example between full 145 00:13:35,000 --> 00:13:40,000 sibling, half-sibling or between parents and their offspring. 146 00:13:40,000 --> 00:13:46,000 This is because these animals share a large portion of the same genes. 147 00:13:47,000 --> 00:13:54,000 for example 50%, 25% in the case of half-siblings or 50% between parents and offspring. 148 00:13:54,000 --> 00:14:00,000 If the contribution of genetic variability to the total variability of a trait is small, 149 00:14:00,000 --> 00:14:05,000 Then based on the phenotype, we can't say much about the value of the animal's genes. 150 00:14:05,000 --> 00:14:09,000 what he will pass on to his offspring. 151 00:14:09,000 --> 00:14:14,000 Inheritance coefficient magnitudes for meat cattle traits 152 00:14:14,000 --> 00:14:21,000 They are mostly highly heritable, shaping up at various levels. 153 00:14:21,000 --> 00:14:27,000 For example, if the tusk length is 0.75 and we have a low heritability coefficient. 154 00:14:27,000 --> 00:14:34,000 Surface area of the eye of round muscle is 0.18. Size of hereditary coefficients. 155 00:14:34,000 --> 00:14:39,000 for most dairy cattle, typical traits are mostly lowly heritable. 156 00:14:40,000 --> 00:14:52,000 ranging from 0.15 to 0.45. High heritability is the percentage of protein in milk trait values. 157 00:14:52,000 --> 00:14:59,000 The heritability coefficients for sheep traits are diverse. 158 00:14:59,000 --> 00:15:04,000 both at the low and high heritability levels. 159 00:15:04,000 --> 00:15:12,000 In most cases, we have examples of traits that are low in heritability, high in heritability can be subjected here 160 00:15:12,000 --> 00:15:22,000 body weight on the hundredth day of life or clean fleece weight, or wool yield. 161 00:15:22,000 --> 00:15:28,000 When it comes to the magnitude of heritability coefficients, heritability for pig traits 162 00:15:28,000 --> 00:15:35,000 These parameters are low level shaping. High level of heritability coefficient 163 00:15:35,000 --> 00:15:41,000 This is the surface of the eye sclera or the amount of meat in primal cuts. 164 00:15:43,000 --> 00:15:51,000 The heritability coefficients for example traits in chickens are also low. 165 00:15:51,000 --> 00:15:58,000 We can mention the highly heritable trait of shell color in the case of non-shell traits. 166 00:15:58,000 --> 00:16:05,000 at a level of 0.7 or in the case of meat characteristics when feed is used. 167 00:16:06,000 --> 00:16:08,000 Thank you very much for your attention.