Report 7: Human Heridity

INTRODUCTION

Human genetics is probably the oldest area applied genetics and homosapiens is certainly an important organism for genetic study, human genetic developed slowly until the last half century. Mendels’s principle, considerable interest was shown in human genetics. Many traits were found to be more prevalent in certain families than in the general population. A few conditions that result in mental retardation depend on single gene substitution and many types mental retardation are genetically and environmentally complex. Human inheritance appeared to be too imprecise and difficult analyze. It most easier and more productive to apply the experimental result method to other animals and plants. Controlled coating among experimental organism were preferred over uncertain human studies.

Identical twin and other combinations of multiple births provide the only human units that approach a genotype standard. When identical twins are separated early in life and experience different environment, one may compare the effect of these environments on similar genotypes. The life span of investigator is no greater than that of the organism being studied. Other difficulties encounter by human geneticist have been associated with incomplete knowledge of human cytology and the genetic mechanism.

Different genetic mechanism can produce identical phenotypes in different families. Polygenes resembles Mendelian genes in transmission but are cumulative in action. The emphasis in human genetic has been on phenotypes rather than genotypes. By contrast, certain manisfestations of a single gene may result strikingly different phenotypes. Different genetic mechanism can produce identical phenotype in different families. In spite of  these difficulties, significant advances have been made in human genetics, combining more traditional approaches with more recent advances in molecular genetics. Today investigation looks at the different aspects  and the role of genetics counselor in human genetics.

The ability to taste PTC (Phenylthiocarbamide) is always used in genetic population. This solution is just able to taste but not to drink, having the unusual property of either tasting very bitter, or being virtually tasteless, depending on genetic makeup of the tester.

LEARNING OUTCOME

We are able to

-          Test the ability of taste PTC

-          Analyze human different of their chromosome, either their genes is dominant or recessive.

-          Calculate the frequencies of phenotypes given student in your class.

METHODS

A.      THE ABILITY TO TASTE PTC

6 beaker was prepare by the instructor

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A piece of filter paper was tip in the beaker number 6 to determine whether or not you are a tester.

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Stop if already taste it

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If not, proceed to the next beaker.

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The number of beaker was record into table 1

B.      SOME READILY DETECTED HUMAN GENETIC TRAITS

Each characteristic was given and identify

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The percentage was calculate and record in a table 2.

BEAKER	NUMBER OF STUDENTS
	GROUP 1	GROUP 2	GROUP 3	GROUP 4	GROUP 5	GROUP 6	TOTAL
6	0	0	0	0	0	0	0
5	4	4	4	5	5	9	31
4	2	0	1	3	3	1	10
3	1	0	1	0	1	0	3
2	0	0	1	0	0	0	1
1	1	0	0	0	0	0	1
TASTELESS	0	0	0	1	0	0	1
TOTAL	8	4	7	9	9	10	47

CHARACTERISTICS	NUMBER OF STUDENTS	PERCENTAGES
The ability to fold tongue
Able to fold tongue [F_]	42	76.36%
Unable to fold tongue [ff]	13	23.63%
Ear lobe
Attached ear lobe [E_]	10	18.18%
Free ear lobe* [ee]	45	81.81%
Cheek
Dimple [D_]	6	10.9%
Smooth  [dd]	49	89%
Hair ‘whorl’
Clockwise [C_]	36	65.45%
Anticlockwise [cc]	19	34.54%
Hair line
Widow’s peak [P_]	12	21.81%
Straight hair line [pp]	43	78.18 %
Ear seruman
Dry ear seruman [W_]	19	34.55%
Wet ear seruman [ww]	36	65.45%

QUESTION AND ANSWER

1.     What is heredity?

Heredity is the heritance by the parent  during the fertilization of the gametes.

2.     Is the ability to taste PTC inherited?? If yes, how it can be inherited.

No

3.     What is the advantages to know whether are in dominant and recessive genotype.

The advantages is we can know the future offspring, predict the offspring and help in genetic analysis

4.     Differentiate between dominant  and recessive gene? Give some examples.

Dominant gene will appear over the recessive gene. The genotype of recessive allele are written in small letter while the dominant is the capital letter.

DISCUSSION

Some people in this world will not inherit the dominant gene only. From the experiment of the human genetic traits, I can observed most student are dominat to fold tongue. For ear lobe, the dominant have less number rather than the free ear lobe. This mean that the free ear lobe which is recessive have large number than the dominant  gene. For the cheek, the student who have dimple is dominant. As we all see, not all student have dimple. The recessive number which is smooth have large number. For the hair whorl, the clockwise hair whorl is dominant and the anticlockwise is recessive. The hairline widow is dominant but have small number then the straight line have the large number. Lastly the dry ear seruman is dominant over the recessive.

For the PTC result, most student are able to taste in the fifth beaker and also have a student that also cannot taste the PTC. Eventhough cannot taste the PTC, it doesn’t meant that the taste sense  is destroy. 

CONCLUSSION

As a conclusion, we are able to test the ability of taste PTC and also able to analyze human different of their chromosome, either their genes is dominant or recessive. Lastly we are able to calculate the frequencies of phenotypes given student.

REFERENCES

Brooker, R. J. (2009). Genetics Analysis & Principle. Third edition: Mc Graw Hill Companies Inc.

Campbell O.N. (2005). Biology. Seventh Edition: Benjamin Cumming.

Eldra P. S., Linda R. B. and  Diana W.M. (2005). Biology. Third Edition: Thomson Brooks/Cole.

Kenneth R. M.,and Joseph L. (2004). Prentice Hall Biology. Teacher's Edition: Pearson Publishing.

Report 6: Human Chromosome

INTRODUCTION
Any of the organized components of each cell which carry the individual's hereditary material, deoxyribonucleic acid (DNA). Chromosomes are found in all organisms with a cell nucleus (eukaryotes) and are located within the nucleus. Each chromosome contains a single extremely long DNA molecule that is packaged by various proteins into a compact domain. A full set, or complement, of chromosomes is carried by each sperm or ovum in animals and each pollen grain or ovule in plants. This constitutes the haploid (n) genome of that organism and contains a complete set of the genes characteristic of that organism. Sexually reproducing organisms in both the plant and animal kingdoms begin their development by the fusion of two haploid germ cells and are thus diploid (2n), with two sets of chromosomes in each body cell. These two sets of chromosomes carry virtually all the thousands of genes of each cell, with the exception of the tiny number in the mitochrondria (in animal), and a few plant chloroplasts. See also Deoxyribonucleic acid (DNA); Gene.
Chromosomes can change their conformation and degree of compaction throughout the cell cycle. During interphase, the major portion of the cycle, chromosomes are not visible under the light microscope because, although they are very long, they are extremely thin. However, during cell division (mitosis or meiosis), the chromosomes become compacted into shorter and thicker structures that can be seen under the microscope. At this time they appear as paired rods with defined ends, called telomeres, and they remain joined at a constricted region, the centromere, until the beginning of anaphase of cell division. See also Cell cycle; Meiosis; Mitosis.
Chromosomes are distinguished from one another by length and position of the centromere. They are metacentric (centromere in the middle of the chromosome), acrocentric (centromere close to one end), or telocentric (centromere at the end, or telomere). The centromere thus usually lies between two chromosome arms, which contain the genes and their regulatory regions, as well as other DNA sequences that have no known function. In many species, regional differences in base composition and in the time at which the DNA is replicated serve as the basis for special staining techniques that make visible a series of distinctive bands on each arm, and these can be used to identify the chromosome.
Each nucleus in the cell of a human or other mammal contains some 6 billion base pairs of DNA which, if stretched out, would form a very thin thread about 6 ft (2 m) long. This DNA has to be packaged into the chromosome within a nucleus that is much smaller than a printed dot. Each chromosome contains a single length of DNA comprising a specific portion of the genetic material of the organism. Tiny stretches of DNA, about 140 base pairs long and containing acidic phosphate groups, are individually wrapped around an octamer consisting of two molecules of each of the four basic histone proteins H2a, H2b, H3, and H4. This arrangement produces small structures called nucleosomes and results in a sevenfold compaction of the DNA strand. Further compaction is achieved by binding the histone protein H1 and several nonhistone proteins, resulting in a supercoiled structure in which the chromosome is shortened by about 1600-fold in the interphase nucleus and by about 8000-fold during metaphase and anaphase, where the genetic material must be fully compacted for transport to the two daughter cells. At the point of maximum compaction, human chromosomes range in size from about 2 to 10 micrometers in length, that is, less than 0.0004 in.

LEARNING OUTCOMES
We are able to

1.    prepare the karyotype of human leukocyte chromosome and

2.    also determine the nmber of chromosome present, sex of the individual and presence or absence or structural chromosome aberration.

METHODS
Preparation of karyotypes

1.    The banding patterns, size and shape of the chromosome in figure 6.1, 6.2 and 6.3 was examine and prepare it.

DISSCUSSION
Human cells have 23 pairs of large linear nuclear chromosomes, giving a total of 46 per cell. In addition to these, human cells have many hundreds of copies of the mitochondrial genome. Sequencing of the human genome has provided a great deal of information about each of the chromosome.
Each diploid (2n) organism has a characteristic number of chromosomes in each body (somatic) cell, which can vary from two in a nematode worm and one species of ant, to hundreds in some butterflies, crustaceans, and plants. The diploid number of chromosomes includes a haploid (n) set from each parent. Many one-celled organisms are haploid throughout most of their life cycle. The human diploid number is 46.
There is some relationship between the number of chromosomes and their size. Some of the chromosomes in certain classes of organisms with large numbers of chromosomes are very tiny, and have been called microchromosomes. In birds and some reptiles, there are about 30–40 pairs of microchromosomes in addition to 5–7 or so pairs of regular-sized macrochromosomes. The number of microchromosomes is constant in any species carrying them, and only their size distinguishes them from the widespread macrochromosomes. At least seven microchromosomes in birds have been shown to contain genes, and all are thought to.
A telomere caps each end of every chromosome and binds specific proteins that protect it from being digested by enzymes (exonucleases) present in the same cell. Most important, the telomere permits DNA replication to continue to the very end of the chromosome, thus assuring its stability. The telomere is also involved in attachment of the chromosome ends to the nuclear membrane and in pairing of homologous chromosomes during meiosis. The structure of telomeric DNA is very similar in virtually all eukaryotic organisms except the fruit fly (Drosophila). One strand of the DNA is rich in guanine and is oriented toward the end of the chromosome, and the other strand is rich in cytosine and is oriented toward the centromere. In most organisms, the telomere consists of multiple copies of a very short DNA repeat.
The centromere is responsible for proper segregation of each chromosome pair during cell division. The chromatids in mitosis and each pair of homologous chromosomes in meiosis are held together at the centromere until anaphase, when they separate and move to the spindle poles, thus being distributed to the two daughter cells. The kinetochore, which is the attachment site for the microtubules that guide the movement of the chromosomes to the poles, is organized around the centromere. The molecular structures of centromeres in most species are still unclear. The repetitive DNA making up and surrounding the centromere is called heterochromatin because it remains condensed throughout the cell cycle and hence stains intensely.


The differences between the karyotypes
Chromosomal mutations produce changes in whole chromosomes (more than one gene) or in the number of chromosomes present.

• Deletion - loss of part of a chromosome
• Duplication - extra copies of a part of a chromosome
• Inversion - reverse the direction of a part of a chromosome
• Translocation - part of a chromosome breaks off and attaches to another chromosome

Here are some syndrome and the differences between the syndrome.

• Down's syndrome, usually is caused by an extra copy of chromosome 21 (trisomy 21). Characteristics include decreased muscle tone, stockier build, asymmetrical skull, slanting eyes and mild to moderate mental retardation.
• Cri du chat, which is caused by the deletion of part of the short arm of chromosome 5. "Cri du chat" means "cry of the cat" in French, and the condition was so-named because affected babies make high-pitched cries that sound like a cat. Affected individuals have wide-set eyes, a small head and jaw and are moderately to severely mentally retarded and very short.
• Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4. It is characterized by severe growth retardation and severe to profound mental retardation.
• Edwards syndrome, which is the second most common trisomy after Down syndrome. It is a trisomy of chromosome 18. Symptoms include mental and motor retardation and numerous congenital anomalies causing serious health problems. Ninety percent die in infancy; however, those who live past their first birthday usually are quite healthy thereafter. They have a characteristic hand appearance with clenched hands and overlapping fingers.
• Patau Syndrome, also called D-Syndrome or trisomy-13. Symptoms are somewhat similar to those of trisomy-18, but they do not have the characteristic hand shape.
• Idic15, abbreviation for Isodicentric 15 on chromosome 15; also called the following names due to various researches, but they all mean the same; IDIC(15), Inverted dupliction 15, extra Marker, Inv dup 15, partial tetrasomy 15
• Jacobsen syndrome, also called the terminal 11q deletion disorder.^[51] This is a very rare disorder. Those affected have normal intelligence or mild mental retardation, with poor expressive language skills. Most have a bleeding disorder called Paris-Trousseau syndrome.
• Klinefelter's syndrome (XXY). Men with Klinefelter syndrome are usually sterile, and tend to have longer arms and legs and to be taller than their peers. Boys with the syndrome are often shy and quiet, and have a higher incidence of speech delay and dyslexia. During puberty, without testosterone treatment, some of them may develop gynecomastia.
• Turner syndrome (X instead of XX or XY). In Turner syndrome, female sexual characteristics are present but underdeveloped. People with Turner syndrome often have a short stature, low hairline, abnormal eye features and bone development and a "caved-in" appearance to the chest.
• XYY syndrome. XYY boys are usually taller than their siblings. Like XXY boys and XXX girls, they are somewhat more likely to have learning difficulties.
• Triple-X syndrome (XXX). XXX girls tend to be tall and thin. They have a higher incidence of dyslexia.
• Small supernumerary marker chromosome. This means there is an extra, abnormal chromosome. Features depend on the origin of the extra genetic material. Cat-eye syndrome and isodicentric chromosome 15 syndrome (or Idic15) are both caused by a supernumerary marker chromosome, as is Pallister-Killian syndrome.

CONCLUSSION

As a conclusion, we are able to prepare and determine the karyotypes with the disease and the structure with each chromosome. Human chromosome have a lot of differences with each other eventhough the number of chromosome is the same and slightly different.

REFERENCES

Brooker, R. J. (2009). Genetics Analysis & Principle. Third edition: Mc Graw Hill Companies Inc.

Campbell O.N. (2005). Biology. Seventh Edition: Benjamin Cumming.

Eldra P. S., Linda R. B. and  Diana W.M. (2005). Biology. Third Edition: Thomson Brooks/Cole.

Kenneth R. M.,and Joseph L. (2004). Prentice Hall Biology. Teacher's Edition: Pearson Publishing.

Report 5: Meiosis in angiosperm , microsporogenesis

INTRODUCTION :
Meiosis is the second important kind of nuclear division. It resembles mitosis in many ways but the consequences of meiotic divisions are very different from those of mitotic divisions. While mitotic division may occur in almost any living cell of an organism, meiosis occurs only in special cells. In animals, meiosis is restricted to cells that form gametes (eggs and sperm). Each species has a characteristic number of chromosomes per somatic cell. Fruit flies have 8; normal humans have 46. They exist as homologous pairs (partners) that are similar in size and shape and carry the same kinds of genes. Thus humans have 23 homologous pairs. The full complement of 46 chromosomes is referred to as the diploid number (referring to the fact that each kind of chromosome is represented twice). In higher organisms when an egg is fertilized the egg and sperm fuse to form a single cell called a zygote which develops into a new organism. If the egg and sperm were both diploid (46 chromosomes each in the case of humans) then the resulting zygote would be tetraploid. This would be an intolerable situation, so a mechanism has evolved to insure that each gamete (egg or sperm) contains only one representative of each homologous pair (or half the diploid number). This is referred to as the haploid number.
In this experiment, the meiotic process is occurs in angiosperm. Pollen mother located in anthers undergo meiosis and form microspores. The haploid nucleus of each microspore subsequently divides mitotically to give rise to a three nucleate male gametophyte. Pollen grains in the anthers are transferred to the stigma of the pistil by insects or wind. There they germinate and begin to grow a pollen tube, which passes down the style and into the ovary of the pistil. The pollen tube carries the sperm nuclei to the ovule. The pollen tube enter the ovule through the ovule through a pore in the integuments called the micropyle; once inside the ovule, the pollen tube burst and frees the sperms nuclei inside the female gametophytes. The pollen tube nucleus then disintegrate.
Double fertilization occurs in angiosperms. One of the sperm nuclei carried into the gametophyte unites with the egg to form diploid zygote subsequently divide mitotically to give rise embryo. The second sperm nucleus unites with the two polar nuclei of the female gametophytes.

LEARNING OUTCOMES:
1. Prepare an aceto-orcein squash of anthers from a flower buds.
2. Demonstrate the stage of meiosis in microsporogenesis.
3. Identify the basic features of meiosis

MATERIALS
1. 70% ethyl alcohol
2. Absolute ethyl alcohol
3. Acetocarmine stain in dropping bottle
4. Bunsen burner
5. Cover slip
6. Teasing needles
7. Forceps
8. Compound Microscope
9. Scalpel or razor blade
10. Slides
11. Supply of immature flower buds (chives)
12. Watch glass

METHODS
1. An individual flower bud was remove from the storage container and was placed in a watch glass. A few drops of 70% ethyl alcohols were added to keep the anther moist.
2. Individual flower buds moist in alcohol were continually kept to dissect the anthers from the bud.
3. Some anther was transfer to a clean microscope slide and was placed in a drop of aceto-orcein stain. A teasing needle was use to macerates the anthers, freeing the microsporocytes from the anther walls.
4. A cover slip was applied and was heat over the Bunsen burner. Stain was added to prevent dying.
5. Paper toweling was use to cover the slide after heating and was press down firmly with thumb. This will flatten the microsporocytes and make it possible to observe the chromosome in the various meiotic stages.
6. If anther from more than one flower is crushed, different stages are likely to be observed. The slide was observed by using the compound microscope.

RESULT

MEIOTIC STAGES	NAME OF PLANT : CHIVES / KUCHAI
	SLIDE 1	SLIDE 2	SLIDE 3
PROPHASE 1	a
LEPTONEMA
ZYGONEMA
PACHYNEMA
DIPLONEMA
DIAKINESIS
METAPHASE I
ANAPHASE I
TELOPHASE I	a	a
PROPHASE II
METAPHASE II
ANAPHASE II
TELOPHASE II	a	a
MATURE POLLEN GRAIN

QUESTION AND ANSWER
1. Does crossing over occur before or after chromosome duplication in cells going through meiosis?
Crossing over occurs after the chromosome duplicate because the chromosome duplicate during the S phase.
2. What visible characteristics of chromosome indicate that they have undergone crossing over during meiosis?
The formation of chiasma where the place occur the crossing over.
3. During meiosis, when does the chromosomes disjunction occur? When does chromatid disjunction occur?
Anaphase I.Anaphase II.
4. In flowering plants such as kuchai, two nuclei from the pollen grain participate in the events of fertilization. With which nuclei from the female gametophyte do these nuclei combine? What tissues are formed from the fertilization events? This event is called double fertilization.
The pollen grain contains 2 nuclei will develop to form two sperm microsporocyte. One of the sperm fuse with ovum and another one fuse with polar nuclei. This will form triploid endosperm tissue that provides food for the seed.

DISCUSSIONS:
From this experiment, I can observed the prophase I, telophase I and telophase two. In prophase I, I determined this stages because of the chromosome are condensed and the color of the center of the cell are darker then each cell. For telophase I, I observed that the cell is dividing into 2 clusters and for telophase II I observed that there are four clusters in one cells.
In prophase I of meiosis I, there are 5 sub-stages. The first one is leptotene where the chromosome starts to condense. Followed by zygotene was the pairing of the homologous chromosome ad become closely associated during synapsis and the formation of the Synaptonemal complex. The third sub-stage is pachytene were the crossing over occur, forming chiasmata, which hold homologous chromosome together. In diplotene, the Synaptonemal complex start to disappear and in the last stage, diakinesis, the Synaptonemal complex is completely disappearing.
In metaphase I, the pair of homologous chromosome aligns along the metaphase plate in double row. The formation of chiasmata before are to help keep the pairs together and position the pairs such that only one side of each homologue’s centromere faces outward toward of the cell’s poles. Thus kinetochore microtubules attach to only one side of each centromere; a kinetochore microtubules from one pole of the cell attaches to one homologue of the chromosome while a kinetochore microtubules from the other cell poles attaches to other homologue.
In anaphase I, kinetochore microtubules shorten and homologous pairs are pulling apart. One duplicated homologue goes to the other poles. Sister chromatids do not separate. This is in contrast to mitosis, where duplicated homologues line up individually on the metaphase plate, kinetochore microtubules from opposite poles of the cell attach to opposite sides of one homologue’s centromere, and sister chromatids are pulled apart in anaphase.
In telophase I, the separated homologues form a cluster at each poles of the cell, and the nuclear membrane re-forms around each daughter cell nucleus. Cytokinesis may occur. The resulting two cells have half the number of chromosome as the original cell. Each chromosome is still in the duplicated state and consists of two sister chromatids, but sister chromatids are not identical because crossing over has occurred.
During prophase II, a new spindle apparatus forms in each cells and the nuclear membrane breaks down and disappears. In metaphase II, a complete spindle apparatus is in place in each cell. Chromosome consisting of sister chromatids joined at the centromere aligns along the metaphase place in each cell. Now kinetochore microtubules from opposite poles attach to opposite side of the same centromere.
When microtubules are shortening in anaphase II, the centromeres split and sister chromatids are pulled to opposite poles of the cells. In telophase II, the nuclear membranes re-form around four different clusters of chromosomes. After cytokinesis, four haploid cells are produce. NO two cells are alike due to the genetic recombination (crossing over) that occurred during prophase I.

CONCLUSION:
As a conclusion, we are able to prepare an aceto-orcein squash of anthers from the flower bud. We also able to demonstrate the stages of meiosis in microsporogenesis. We are also able to identify the basic features of meiosis as it occurs in angiosperm.

REFERENCES: 
Brooker, R. J. (2009). Genetics Analysis & Principle. Third edition: Mc Graw Hill international edition.
Eldra P. Solomon, Linda R. Berg, and Diana W.Martin. (2005). Biology. Third Edition: Thomson Brooks/Cole.
Kenneth R. Miller,and Joseph Levine. (2004). Prentice Hall Biology. Teacher's Edition: Pearson Publishing.
Campbell O'N. (2005). Biology. Seventh Edition: Benjamin Cumming.