eChapters

Biological assay or bioassay

• A bioassay is an analytical method to determine the concentration or potency of a substance by its effect on living animals or plants (in vivo), or on living cells or tissues (in vitro).

• Bio-assays are thus a type of experiments with the object of comparing the efficacy of two or more substances, or preparations, like drugs, by using responses produced by them on suitable living organisms.

• The bio assay involves a stimulus applied to a subject and the response of the subject to the stimulus.

• When a stimulus is applied to a subject there may be a change in some characteristics of the subject. Such changes in the subject are known as responses.

• The response may be quantitative as in the case of weight or qualitative as in the case of mortality. The magnitude of response depends upon the dose.

• Normally, two preparations having a common effect are taken for assaying. One of the preparations is of known strength and is called the standard preparation and the other is of unknown strength and is called test preparation.

REGRESSION

Regression means to revert or return back. The term was first introduced by Sir Francis Galton in1877. Regression technique is applicable in all those fields where two or more relative variables have the tendency to go back to the mean. Regression analysis refers to the methods by which estimates are made of the values of a variable from the knowledge of the values of one or more other variables and to the measurement of the errors involved in this estimation pro- cess.

In statistical modeling, regression analysis is a statistical process for estimat- ing the relationships among variables. It includes many techniques for mod- eling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables. Regres- sion analysis helps one understand how the typical value of the dependent variable (or ‘criterion variable’) changes when any one of the independent variables is varied, while the other independent variables are held fixed. Most commonly, regression analysis estimates the conditional expectation of the dependent variable given the independent variables – that is, the average value of the dependent variable when the independent variables are fixed.

ANALYSIS OF VARIANCE

Analysis of Variance (ANOVA) is a hypothesis-testing technique used to test the equality of two or more population (or treatment) means by examining the variances of samples that are taken. ANOVA allows one to determine whether the differences between the samples are simply due to random error (sampling errors) or whether there are systematic treatment effects that cause the mean in one group to differ from the mean in another.

Most of the time ANOVA is used to compare the equality of three or more means, however when the means from two samples are compared using ANOVA it is equivalent to using a t-test to compare the means of independent samples.

ANOVA is based on comparing the variance (or variation) between the data samples to variation within each particular sample. If the between variation is much larger than the within variation, the means of different samples will not be equal. If the between and within variations are approximately the same size, then there will be no significant difference between sample means.

The two-way ANOVA compares the mean differences between groups that have been split on two independent variables (called factors). The primary purpose of a two-way ANOVA is to understand if there is an interaction be- tween the two independent variables on the dependent variable. For example, you could use a two-way ANOVA to understand whether there is an interac- tion between gender and educational level on test anxiety amongst university students, where gender (males/females) and education level (undergraduate/ postgraduate) are your independent variables, and test anxiety is your depen- dent variable. Alternately, you may want to determine whether there is an in- teraction between physical activity level and gender on blood cholesterol con- centration in children, where physical activity (low/moderate/high) and gender (male/female) are your independent variables, and cholesterol concentration is your dependent variable.

The interaction term in a two-way ANOVA informs you whether the effect of one of your independent variables on the dependent variable is the same for all values of your other independent variable (and vice versa). For example, is the effect of gender (male/female) on test anxiety influenced by educational level (undergraduate/postgraduate)? Additionally, if a statistically significant interaction is found, you need to determine whether there are any “simple main effects”, and if there are, what these effects are (we discuss this later in our guide).

Variation in Chromosome Structure

Natural variation exists in chromosome structure

Changes in chromosome structure include deletions, duplications, inversions, and translocations

The loss of genetic material in a deletion tends to be detrimental to an organism

Duplications tend to be less harmful than deletions

Duplications provide additional material for gene evolution, sometimes leading to the formation of gene families

Copy number variation is relatively common among members of the same species

Comparative genomic hybridization is used to detect chromosome deletions and duplications

Inversions often occur without phenotypic consequences

Inversion heterozygotes may produce abnormal chromosomes due to crossing over

Translocations involve exchanges between different chromosomes

Individuals with reciprocal translocations may produce abnormal gametes due to the segregation of chromosomes

Abstract

The data on production performance of Banni buffaloes during the 2008-09 and 2009-10 were collected from the animals selected under project “In-Situ Conservation of Banni buffalo”. The data on 208 animals were analyzed and overall means ± SE for total lactation milk yield, lactation length, peak yield, days to attain peak yield, milk yield per day of lactation length, service period and calving interval were observed as: 2917.76 ±  54.77 lit., 292.19 ± 2.88 days, 14.86 ± 0.18 lit., 47.50 ± 2.92 days, 9.99 ± 0.14 lit., 87.13 ± 4.39 days and 380.87 ± 2.36 days, respectively. Present findings on production performance indicate Banni buffalo an valuable germplasm maintained under extensive production system and arid climatic conditions of Kachchh and holds the promise of raising milk production of non-descript and low producing buffaloes through up-grading and crossbreeding. Therefore, Banni buffalo can be use as improver breed for genetic improvement of non-descript buffalo population in semi-arid and arid regions of the state / country.

Introduction

Uttarakhand has a mix of almost all domesticated species of livestock, very large in number and very low in productivity across the board. In economic terms they are a wealth indeed, low productivity not with standing, as the sector supports livelihoods of nearly 80 percent of the rural households in the state, at least in part in the majority of cases and in full in some (tribal and nomads exclusively living off livestock).

Livestock production in Uttarakhand is the endeavor of the small holder (marginal, small and landless) and takes place in millions of small and tiny holdings scattered across the state. The predominant farming system is mixed crop livestock farming, both in the plains as well as the hills, irrigated in the plains and rainfed in the hills.

There are certain inherited traits (characters) in various species of livestock which are economically important. These traits have to be improved for increased production like milk, meat, egg, wool, etc.

Quantitative Versus Qualitative Inheritance

There is a continuum of traits being inherited as a Mendelian trait with simple inheritance and traits having quantitative inheritance without well separated classes and with many genes involved.
Classification of traits in relation to mode of inheritance and environmental tolerance are shown in Figure 1.2. First there are the well known traits with simple Mendelian mode of inheritance. The trait with quantitative genetic inheritance is caused by segregation of many gene pairs, each with small effect. At the same time the trait is influenced by a lot of minor environmental effects.
Diseases will often be ‘either/or traits’ as the simple Mendelian traits. Cases in which the severity of the disease has a normal distribution can also be found. In many production diseases the disease only occurs when a genetically prone individual is exposed to adverse environmental effects. Figure 1. Classification  of traits in relation to mode of inheritance  and environmental tolerance. 
 

The amount of variation is measured and expressed as the variance. When values are expressed as deviations from the population mean the variance is simple the mean of the squared values. For example, the genotypic variance is the variance of genotypic values and the environmental variance is the variance of environmental deviations. The total variance is the phenotypic variance of the variance of phenotypic values, and is the sum of the separate components. 

Introduction

Genetic resistance to diseases is a great resource to control and prevent diseases, and to improve the productivity in livestock and poultry. The emergence of virulent and drug resistant pathogens, restriction on use of antimicrobials and appearance of certain diseases associated with selection for production traits emphasize the possible exploration for genetic resistance to diseases (Pinard et al., 1992). Genetic resistance to diseases is a composite trait and difficult to measure directly. The disease resistance measurement was first started as difference in mortality among populations. Later on, several other criteria related to expression of infection such as antibody response, tumour production count or expression in quantitative scale such as survival time and density of pathogen in target organs were used as a measure of disease resistance.

Individuality tells us what an animal seems to be; his pedigree tells us what he ought to be, but the performance of his progeny tells us what he is
Effectiveness of selection depends on ability to recognize those animals, which possess superior inheritance. Those superior animals must be mated together for the production of offspring. The aids available to estimate the breeding value of an animal is through the phenotype of an animal or its relatives.

Introduction

Nanocomposites are materials that incorporate nanosized particles into a standard material matrix. The addition of nanoparticles can significantly improve properties such as mechanical strength, toughness, electrical or thermal conductivity. Typically, only a small amount of material (0.5-5% by weight) is required due to the effectiveness of the nanoparticles. A nanocomposite is a solid material that consists of multiple phases, where at least one of the phases has one, two, or three dimensions in the nanometer size range. The goal of the nanoscale phase process is to achieve synergy between different constituents. Nanocomposites represent a promising alternative to overcome current limitations of microcomposites and monolithics, and are becoming the materials of the future (Schmidt et al., 2002).

Introduction

Non-coding RNAs (ncRNAs) are RNA molecules that do not code for proteins. They are transcribed from DNA and can be categorized into two main types: long non-coding RNAs (lncRNAs) and small non-coding RNAs (sncRNAs). While sncRNAs are shorter than 200 nucleotides, lncRNAs are usually longer than 200 nucleotides. Non-coding RNAs have been found to play important roles in a variety of cellular processes, including gene expression, cell differentiation, and development.

There are other groups that contribute to the reactivity of enzymes beside amino acid residues.

These groups are called cofactors - chemicals required by apoenzymes (inactive) to become holoenzymes (active).

There are two types of cofactors:

1. Essential ions - metal ions -inorganic
2. Coenzymes - organic molecules that act as group-transfer reagents (accept or donate groups)- can also be H⁺ and/or e^-

Both provide reactive groups not found on amino acids side chains.

Coenzymes can be either cosubstrates (loosely bound to enzyme; is altered, then regenerated) or prosthetic groups (tightly bound to enzyme).

Coenzymes can be classified by their source:

(Chroma - Colour; Some - Body)
A chromosome is a thread-like self-replicating genetic structure containing organized DNA molecule package found in the nucleus of the cell. Clear and detaile decriptions of mitotic chromosomes in plants and animals were published by Strasburger in 1875 and by the German scientist Walter Flemming in 1879- 1882.Heinrich Wilhelm Gottfried Waldeyer coined the term chromosome in 1888.
Normally Chromosomes are of two types
Autosomes - Control characters other than sex characters or carry genes for somatic characters.
Sex chromosomes (S    
Humans and most other mammals have two sex chromosomes X & Y, also called heterosome, odd chromosome, or idiosome. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome. In birds the female (ZW) is hetero-gametic and male (ZZ) is homo-gametic.
Haploid: Haploid cells (N) have only one copy of each chromosome.
Diploid: Diploid cells (2N where N- chromosome number) have two homologous copies of each chromosome. The body cells of animals are diploid.In animals, gametes (sperm and eggs) are haploid.
Homologous Chromosomes
Diploid organisms have two copies of each chromosome (except the sex chromosomes). Both the copies are ordinarily identical in morphology, gene content and gene order and hence known as homologous chromosomes.Each pair of chromosomes made up of two homologs.
Homologous chromosome is inherited from separate parents; one homolog comes from the mother and the other comes from the father.