# The character of diploid variation chromosome set of animal species Bos Taurus, Bos Grinniens, Ovis Aries and Equus Caballus.

INTRODUCTIONAnalysis of chromosomes in the cells of plants and animals of different species revealed a number of general laws of importance in the study of the phenomena of heredity and variation. Typically, there are double chromosomes in somatic cells, and a set of chromosomes in the cells is diploid (2n). Nevertheless, various kinds of animals are characterized by a variety of karyotypes variability. Spontaneous changeable of karyotype the somatic cells, which happening with some periodical in each animal are reflection of genetic conditions of the organism. The main type of spontaneous karyotype disorders in somatic cells are different genomic and chromosomal mutations (numerical variations)--aneuploidy and polyploidy. The creation of aneuploidy cells to animals preferably occurs equally at the expense of loss and due to no disjunction chromosomes during mitosis process. The combination of these disorders probably reflects the degree of genetic determination of spontaneous karyotype disorders in an animal organism, which arising in somatic tissues on the different period's cells circles, and high periodicity their meet it can influencing on productive and reproductive quality of animals [1- 4]. According to research worker the level of spontanea changeable of karyotype in animal of species Bos Taurus, Bos Grinniens, Ovis Aries, and Equus Caballus is fluctuating on an average 3, 8 to 24,5% [5- 8, 1, 3-4]. We undertook a study of the basic statistical parameters of diploids set of chromosomes and determination the nature of the distribution of cattle, yaks, sheep and horses on a normal diploid karyotype.

MATERIALS AND METHODS

As the materials in the study served the drugs of metaphase chromosomes derived from different species of animals in the genus Bos Taurus, Bos grinniens, Ovis aries, Equus caballus, bred in the Kyrgyz Republic and the Republic of Kazakhstan. Chromosome preparations were prepared by conventional methods. Under the microscope MBI -15 randomly selected from each of the animal species were studied 200 metaphase cells. In each studied cell chromosomes numbers were counted. The basic statistical parameters ([bar.x], [sigma], [C.sub.v], t, P) of the diploid number of chromosomes were calculated using the well-known formulas. To determine the theoretical frequency of variation range of the studied trait was used the normal distribution function I (f (t)), for which the equation of Gauss--Laplace was exposed to following contraction:

[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]

where [y.sub.x]--is an unknown ordinate of normal curve showing the theoretical frequency for the particular value of this varying attribute; n--the number of observations, X--average arithmetic mean, x--the value of varying trait; [sigma]--standard square deviation; [pi] and e--are mathematical constants; f(t)--the normal distribution function I. When comparing the empirical and theoretical (calculated) series on the distribution of the number of chromosomes Pearson's chi-squared ([chi square]) test was used in modification of Yastrzemski B.S. [9]: J = [absolute value of C-N]/[square root of 2N - 4[theta]], where J--is a criteria of Yastrzemski; C = [SIGMA] ([f.sub.emp] - [f.sub.theor]) / [f.sub.theor]q;

N--the number of classes of the variational series (the difference [absolute value of C-N] taken nonmetering the sign); [theta] value depending on N. Since the number of classes is typically less than 20, the value of 46 can be taken as equal to 2,4; q = 1- p, where p = p=f(t), and a [f.sub.emp] [??] [f.sub.theor]--respectively empirical and theoretical frequency of the series. Kurtosis exponent ([E.sub.x]) was calculated by the formula [E.sub.x] = [[mu].sub.4]/[[sigma].sup.4]-3, where [[mu].sub.4]--is the fourth central moment; [[sigma].sup.4]--standard deviation, taken in the fourth degree. To determine the parameter of the parent population (p) was used the criterion of normalized deviation.

RESULTS AND DISCUSSION

In the analysis of genetic data, there are different types of distribution of the population on the magnitude of varying trait. Among the most common there is a normal distribution, which is characterized by the accumulation of variants in the central classes and a gradual decrease in their numbers as the distance from the center of the species is becoming remote. Regularities of this distribution allow determining the frequency of most empirical series, although the curve of the last variation deviates from the normal curve. The bulk of the analyzed cells are characterized by normal diploid chromosomes for cattle--79.80%, yak--78.60%, horses 74,56% and sheep--75.89%. The bulk of heteroploidy is constituted of hypoploid cells; apparently this is due to the action of the hypnotizing solution on arrangement of chromosomes in metaphase cells. Chromosomes' set, fixed in the long-term evolution, is the most important specific character, so it should be characterized by high stability, but the defined differences in this case should be minor. This position was confirmed in our study (Table 1). The coefficient variability of the diploid number of chromosomes in all cases, even less than 2.0%.

Due to the fact that the study parameter is fairly constant sign, the degree of its variation is largely dependent on the absolute magnitude of a set of chromosomes, which is characteristic for each type of organism. The correlation coefficient between these attributes in the studied species is close to unity (r = 0,99995).

The nature of variation of the number of chromosomes in the studied objects are presented in Table 2 which presents the data on the distribution of cells by class and frequency of theoretical and empirical series. From the data of the table it is shown that most of the accumulated variation is gathered the fifth form and this is natural, since this class corresponds to a normal diploid set of chromosomes (sheep--54, cattle and yak--60, horses 64). Whereas the proportion of metaphase cells with extremes (2n-3, 2n-4, 2n +2, 2n +3) does not exceed three percent. From Table 2, we can see a significant predominance of hypoploid cells compared to hyperploid. In this connection it should be noted that a significant number of hypoploid cells has an artifact origin, so the selection of cells to account should be more carefully. The overwhelming majority of hypoploid cells characterized with a loss of autosomes of smaller groups. Generally, to determine the frequency of aneuploidy there should be considered metaphase cells with a diploid number of chromosomes--2n [+ or -] 1; 2n [+ or -] 2. As a result, the frequency of aneuploidy in sheep was equal to 17.60%, cattle -15.99%, yak -17.21% and horses--18.73%. Our data on a set of chromosomes and the frequency of aneuploidy is consistent with other researches [10-12, 1,3,6-8].

Empirical variance series and schedule does not allow to judge with full confidence about the patterns of distribution of population, since the value of any varying attribute is influenced by numerous, including random ones, factors that distort the objective picture of the variation.

Yet the knowledge of the nature of distribution allows to avoid possible errors in the assessment of general parameters for sample data. From Table 2, we can visually see the discrepancy between empirical and theoretical frequency series, so for more accurate testing of the marked difference we used the criteria for matching [chi square] and Yastrzemski's criteria (table 3). Approval criteria, calculated using the Pearson's chi-squared ([chi square]) test for each type of tested animals was significantly greater than their standard value ([[chi square].sub.emp] > [[chi square].sub.theor]).

Similar results were obtained using the criterion of Yastrzemski (J), which indicates the degree of similarity between the compared frequencies and has a continuous distribution function and is subject to the normal law. As in all cases, J>3, the discrepancy between the empirical and theoretical distributions for the chromosome number of animals may be considered as significant.

Conclusion:

The calculated value of the criterion of Yastrzemski in all groups was several times greater than their expected values (from 10.00 for yak to 45.15 for cattle), it is followed from this that the distribution of metaphase cells in chromosome number in the studied animals are not subject to patterns of the normal distribution. The above mentioned case is clearly illustrated in Figure 1, where the difference is clearly visible in the distribution of the empirical and the theoretical curve of the number of chromosomes in the studied species.

As it can be seen in this Figure in the distribution of cells according to the number of chromosomes in the experimental animals marked a clear peaked ness, which is a characteristic property of the excessive curve, at the same time, to some extent there was marked negative skew, as the top of the empirical variation of the curve is to the right of the center of the distribution (the curve skewed to the right).

Therefore, to determine the type of distribution of the studied indicator there were analyzed coefficient of excess and asymmetry coefficients (Table 3). Since empirical values and defined values Ex and As in all cases exceed the critical value table, it can be concluded that the in the studied curves the asymmetry and excess are significant. A comparative analysis of these two factors can show that the distribution of the number of chromosomes in the studied species rather follows the laws of excessive type of distribution, as Ex in absolute value and reliability stands out from the As. However, in such cases for the integration of information in determining the number of theoretical frequency of excessive series should be used the formula of Charlie, where along Ex As is calculated as well.

Summary:

The conformity of metaphase cells distribution of cattle, yaks, sheeps and horses in accordance with aim -it of chromosomes (2n) to excessive curve is considered in the article.

ARTICLE INFO

Article history:

Received 15 April 2014

Received in revised form 22 May 2014

Accepted 25 May 2014

Available online 15 June 2014

REFERENCES

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[5] Begimkulov, B.K., 1995. Variability of normal karyotype yak, zebu and their hybrids with cattle. In the Proceedings of the International Scientific Conference of the Kyrgyz Agrarian Academy. Bishkek, 3: 6365.

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[7] Sharipov, I.K., 1995. Cytogenetically studies of Kazakhstan sheep, Ph.D.thesis, Uzbekistan Academy of Sciences, Institute of Genetics, Tashkent.

[8] Zhapbasov, R., 1976. Characteristic's sheep karyotype and spontaneous variability of chromosomes in bone marrow cells, Ph. D. thesis, Moscow.

[9] Lakin, G.F., 1990. Biometrics. Moscow, Higher Shkola, pp: 83-90, 145-148.

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(1) Kadyrbai Bekbalaevich Chekirov, (2) Baratbek Kadenovich Begimkulov, (1) Gulbubu Toktosunovna Kurmanbekova, (1) Salkyn Tursunalievna Beyshenalieva, (1) Nurjamal Taychievna Omurzakova

(1) Kyrgyzstan-Turkey Manas University, Mira Avenue, 56, 720042, Bishkek, Kyrgyzstan (2) Kazakh National Agrarian University, Abai street, 8, 050010, Almaty, Republic of Kazakhstan

Corresponding Author: Kadyrbai Bekbalaevich Chekirov, Kyrgyzstan-Turkey Manas University, Mira Avenue, 56, 720042, Bishkek, Kyrgyzstan

Table 1: Characteristics of the number of chromosomes in the studied species. Species of animals Basic statistical parameters Number of the studies [bar.X] [+ or -] metaphase cells, n [m.sub.x] Ovis aries 676 53.682 [+ or -] 0.039 Bos Taurus 807 59.748 [+ or -] 0.031 Bos grinniens 215 59.740 [+ or -] 0.061 Eguus caballus 283 63.668 [+ or -] 0.061 Species of animals Basic statistical parameters [mu] [sigma] [C.sub.v] Ovis aries 53.615-53.759 1.022 1.095 Bos Taurus 59.688-59.809 0.876 1.467 Bos grinniens 59.621-59.858 0.888 1.486 Eguus caballus 63.548-63.778 1.027 1.614 Table 2: Empirical and theoretical frequency of distribution of the number of chromosomes in sheep, cattle, yaks and horses. Rates Animal species Ovis aries W 50 51 52 53 54 [f.sub.emp] 17 21 39 56 513 % 2,51 3,11 5,77 8,28 75,89 [f.sub.theor] 0,40 8,52 67,61 210,75 251,10 % 0,06 1,26 10,02 31,23 37,25 Bos taurus W 56 57 58 59 60 [f.sub.emp] 11 17 45 64 644 % 1,36 2,11 5,58 7,93 79,80 [f.sub.theor] 0,00 2,65 50,71 255,95 352,19 % 0,00 0,33 6,28 21,70 43,61 Bos grinniens W 56 57 58 59 60 [f.sub.emp] 3 4 13 19 169 % 1,40 1,86 6,05 8,84 78,60 [f.sub.theor] 0,00 0,82 14,15 68,47 92.65 % 0,00 0,38 6,58 31,82 43,05 Avg. Bos W 56 57 58 59 60 [f.sub.emp] 14 21 58 83 813 % 1,37 2,05 5,68 8,12 79,55 [f.sub.theor] 0,00 3,47 64,86 324,42 444,84 % 0,00 0,34 6,34 31,72 43,49 Equus caballus W 60 61 62 63 64 [f.sub.emp] 7 9 16 28 211 % 2,47 3,28 5,65 9,89 74,56 [f.sub.theor] 0,19 3,74 29,58 88,95 104,39 % 0,07 1,32 10,45 31,83 36,89 Total W 2n-4 2n-3 2n-2 2n-1 2n [f.sub.emp] 38 51 113 167 1537 % 1,92 2,57 5,70 8,43 77,59 [f.sub.theor] 0,59 15,7 162,1 624.12 800,33 % 0,03 0,79 8,19 31,52 40,41 Rates Animal species Ovis aries W 55 56 57 [SIGMA] [f.sub.emp] 16 8 6 676,0 % 2,37 1,18 0,89 100 [f.sub.theor] 114,78 20,06 0,34 674,9 % 17,01 2,97 0,20 100 Bos taurus W 61 62 63 [SIGMA] [f.sub.emp] 12 8 6 807,0 % 1,49 0,99 0,74 100 [f.sub.theor] 132,13 13,52 0,38 807,5 % 16,36 1,67 0,05 100 Bos grinniens W 61 62 63 [SIGMA] [f.sub.emp] 3 2 2 215,0 % 1,40 0,93 0,93 100 [f.sub.theor] 35,26 3,74 0,31 215,2 % 16,38 1,74 0,05 100 Avg. Bos W 61 62 63 [SIGMA] [f.sub.emp] 15 10 8 1022 % 1,47 0,98 0,78 100 [f.sub.theor] 167,39 17,26 0,49 1022,7 % 16,37 1,69 0,05 100 Equus caballus W 65 66 67 [SIGMA] [f.sub.emp] 6 3 3 283 % 2,12 1,06 1,06 100 [f.sub.theor] 47,20 8,36 0,58 283,0 % 16,68 2,95 0,20 100 Total W 2n+1 2n+2 2n+3 [SIGMA] [f.sub.emp] 37 21 17 1481 % 1,87 1,06 0,86 100 [f.sub.theor] 329,37 45,68 2,41 1980,3 % 16,63 2,31 0,12 100 Table 3: Comparison of empirical and theoretical frequency of chromosome number in different animal species using Pearson's chi-squared ([x.sub.2]) test and criterion of Yastrzemski (J), and evaluation of skewness and the observed distributions excessiveness. Calculated values Animal species [chi square] emp [chi square] theor J Ovis aries 577,56 *** 7,8-11,3-16,3 121,69 Bos taurus 502,77 *** 4,3-9,9 -31,6 129,45 Bos grinniens 125,34 ** 12,7-63,7- 37 30,01 Equus caballus 188,78 *** 4,3- 9,9 -31,6 46,53 Calculated values Animal species As [t.sub.As] Ex [t.sub.Ex] Ovis aries -1,38 14,72 6,90 36,71 Bos taurus -1,50 17,49 8,92 51,79 Bos grinniens -1,32 8,00 8,62 25,99 Equus caballus -1,26 8,72 6,73 23,25 Standard values Animal species Ovis aries J = 3 In case Bos taurus n>200, As = 0,4 Bos grinniens Ex = 0,832 Equus caballus Note: ** - p<0, 01; *** - p<0,001.

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Author: | Chekirov, Kadyrbai Bekbalaevich; Begimkulov, Baratbek Kadenovich; Kurmanbekova, Gulbubu Toktosunovna |
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Publication: | Advances in Environmental Biology |

Article Type: | Report |

Geographic Code: | 9KYRG |

Date: | Jun 1, 2014 |

Words: | 2818 |

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