Turner’s and Klinefelter’s Syndromes

Genetics, classical genetics or Inheritance biology, is the branch of science that deals with the study of the transfer of characters from one generation to another generation. Paternal and maternal transfer their feelings embedded into the chromosome into the progeny. These characters can be determined by the help of monohybrid cross, dihybrid cross, back cross, test cross, self cross and reciprocal cross. Some mutations occur on a biochemical and molecular basis during the transfer of characters.

Mutation can be defined as the genetic variations that lead to permanent changes in the genotype of an organism over a sudden time. Some mutations lead to genetic drift, which can cause the origination of new traits in the species.

The origin of mutation can occur in almost every cell, but somehow some remain undetectable in both somatic cells and germ cells. They arise due to numerous environmental factors like humidity, temperature etc.

These variations are also known as sports or saltations. The mutation term was coined by Hugo de Vries (1901), who also proposed the mutation theory of evolution. The source that he used to study the mutation was plants of Oenothera Lamarckian. These are the mutations that occur because of changes in their chromosome number and chromosomal aberrations.

Basic terminologies should be kept in mind regarding the classical genetics and chromosome syndromes (Turner’s and Klinefelter’s syndrome).

1. Classical genetics: It is the branch of science that deals with the study of the transfer of paternal and maternal characters into offspring. The term genetics is derived from the Greek word “to grow into”, and W.Bateson coined it in 1905. Gregor Mendel is considered the father of genetics. William Bateson defines genetics as “to generate”.
2. Gene: Gene can be defined as the inherited factor which is helpful in the determination of character constituting chromosomes. It is the smallest unit that is transferred into the offspring. Gene possesses different characters and different locus on a chromosome.
3. Allele: Allele is derived from the word allelomorphs and can be defined as the combination of non-sister chromatids of homologous chromosomes, which represents the alternative form of a gene. The allele can be iso allele and pseudo allele. The segregation of alleles takes place in Anaphase I. 
4. Clone: Clone is the carbon copy of maternal or parental characters which is produced asexually using in vitro techniques. Example: Dolly 5 July 1996-14 February 2003. She was mercy-killed. 
5. Offspring: Offspring is biparental by sexual mode of reproduction.
6. Characters: Characters can be defined by our chromosomes which define our phenotype and genotype. 
7. Chromosomes: Chromosomes constitute the genetic information that is transferred to the offspring after fertilisation. Chromosomes are made up of chromatids and chromatids can be classified as sister chromatids and non-sister chromatids. 2 chromatids, 2 kinetochores, 1 centromere result in one chromosome. 
8. Chromatid: The structure of chromatid constitutes telomere, long arm referred to as queue (q), short arm referred as petite (p), centromere.
9. Locus: Locus specifies the location of genes on a chromosome. It can be homologous or non-homologous.
10. Genotype: Genotype can be defined as the genetic constitutes of the organisms like which characters it possesses.
11. Gene pool: A gene pool constitutes all the genotypes of all the organisms of a population.
12. Population: A population is made up of different species.
13. Phenotype: Phenotype tells about the morphology, physical appearance and body structure of an organism.

Genotype determines the. the phenotype of an organism.

1. Mendel characters: Mendel considered Pisum sativum to give 7 characters based on seed its shape and colour, pod its shape and colour, flowers position and colour and stem its length. 
2. Monohybrid cross: Monohybrid cross can be defined as the cross that occurs between a single character out of seven characters given by Mendel. For example, cross between colours (Green, Yellow).
3. Dihybrid cross: Dihybrid cross can be defined as the cross that occurs between the two characters given by Mendel. For example, cross between length (tall, dwarf) and colour (green, yellow).
4. Trihybrid and Polyhybrid cross: These can be defined as the cross that is made between three and more than three characters. 
5. Self cross: A cross that is made between the same genotypes.
6. Back cross: A cross that is made between the filial generation and one of the parental genotypes. 
7. Reciprocal cross: A cross that is made between the reversed sexes means parental is considered as maternal and maternal is considered as parental to carry out this cross. For example, a cross that is made between a tall female and a short man or a cross that can be made between a short female and a tall man. 
8. Ploidy condition: It is a condition that occurs due to changes or variations in the numerical values of chromosomes. It can be divided into euploid or aneuploidy. Euploidy can be divided into monoploidy, diploidy or polyploidy. Aneuploidy can be divided into hypoploidy or hyperploidy. Hypoploidy can be divided into monosomy or nullisomy and hyperploidy can be divided into trisomy or tetrasomy.
9. Euploidy: Euploidy can be defined as the condition in which the somatic cells represent the exact number of copied chromosomes. 
10. Monoploidy: It is a representation of a single set of copied chromosomes. 
11. Diploidy: It is a condition that represents double basic chromosome numbers. 
12. Polyploidy: Polyploidy is a condition that constitutes more than two sets of chromosomes. It is induced due to mechanical injury, variations in temperature, infections, chemicals like colchicine and many more.
13. Aneuploidy: Aneuploidy can be defined as the addition or deletion of one or more than one set of chromosomes from the original genome. Aneuploids can be defined as organisms that are suffering from aneuploidy conditions. 
14. Hypoploidy: Hypoploidy can be defined as the loss of chromosomes from the original set of the genome. 
15. Monosomy: It is an aneuploid condition with the n-1 deficient chromosome. It leads to genetic imbalance. Example: Turner syndrome.
16. Nullisomy: It is an aneuploid condition with a deficiency of homologous chromosomes 2n-2. It leads to the absence of certain genes It is considered lethal to humans. It is caused due to nondisjunction.
17. Hyperploidy: Hyperploidy is a condition that represents having unbalanced sets of chromosomes. 
18. Trisomy: It is a condition of 2n+1. 2n represents the somatic chromosome number. 
19. Tetrasomy: It is a condition of 2n+2. 2n represents the somatic chromosome number.

Turner’s Syndrome(45, X): 

Turner’s syndrome was first discovered by H. H Turner in 1938. It is characterised by hypogonadism. In turner’s syndrome female retarded sexual development. It is a result of a monosomic condition. 

Causes:

Sterility, underdeveloped short stature breasts, reduced size of ovary and uterus, no occurrence of oogenesis process and menstrual cycle, impairment in hearing capabilities, webbing of skin especially the neck muscles and the regions around the neck, infertility, abnormalities in the cardiovascular system, somatic cell constitutes no sex chromatin, hair loss and many more. 

Origin:

Turner syndrome is a result of abnormal zygote development which is formed by the fusion of no X chromosome (abnormal egg) and normal gymnosperm, sperm having X-chromosome or it can occur due to fusion of normal egg with abnormal sperm. 

Klinefelter’s syndrome (47,XXY): 

Klinefelter’s syndrome is a sex chromosome-linked disorder in which the person has 44 chromosomes with one additional X chromosome.

Causes:

Subfertile males showing some feminine characteristics like gynecomastia, feminine pitched voice, long limbs, mental retardation, sparse body hairs, average height, psychopathic tendencies. It can be 48,XXXY or 49,XXXXY. 

Conclusion: 

Inheritance biology is the emerging field of life sciences since the golden era. Due to this branch of science, we are capable of knowing about the various terminologies which are related to hereditary and variations that how genes flow from to offsprings, how we can differentiate ourselves from others based on genotype as well as our phenotypes. In simple words, it tells our origin what we are and which genes can we express that are inherited into us by our parents. We can easily correlate the different traits both genotypically and phenotypically by using Mendel’s laws, hypothesis and crosses. Apart from this, there are some mutations or chromosome aberrations that result in various syndromes and currently, some treatments are available although we can also generate some more treatments by carrying out the crosses with more than three characters and by producing some alterations that can prove themselves to combat the syndromes.