Human Genetics

Experiment

Human Genetics

HumanGenetics

MargaretE. Vorndam,M.S. Version42-0068-00-01

LabReportAssistant

Thisdocumentisnotmeanttobeasubstituteforaformallaboratoryreport.TheLabReportAssistantissimplyasummaryoftheexperiment’squestions,diagramsifneeded,anddatatablesthatshouldbeaddressedinaformallabreport.Theintentistofacilitatestudents’writingoflabreportsbyprovidingthis informationinan editablefilewhichcanbe senttoan instructor.

Observations

Data Table 1: Single-Gene Traits of a Selected Population

Subject # &gt

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Total

XX Female

XX

XX

XX

XX

XX

XX

XX

XX

XX

9

XY Male

xy

xy

XY

XY

Xy

XY

6

FF,Ff = unattached

FF

Ff

FF

Ff

FF

Ff

Ff

FF

Ff

FF

Ff

FF

Ff

13

ff = attached

ff

ff

2

RR,Rr = roller

R

Rr

Rr

RR

Rr

RR

RR

Rr

Rr

Rr

10

rr = can’t roll

rr

rr

rr

rr

rr

5

SS,Ss = straight thumb

Ss

SS

Ss

SS

SS

Ss

Ss

Ss

8

ss = bent thumb

ss

ss

ss

ss

ss

ss

6

MM,Mm = hair

Mm

Mm

Mm

MM

Mm

Mm

MM

MM

Mm

Mm

MM

Mm

Mm

Mm

15

mm = no hair

TT,Tt = left on top

T

T

Tt

Tt

TT

Tt

TT

Tt

Tt

Tt

10

tt = right on top

tt

tt

tt

tt

tt

5

LL,Ll = two tendons

L

Li

L

LL

Ll

Ll

LL

Ll

LL

Ll

LL

11

ll = three tendons

ll

ll

ll

3

Exercise1: PatternsinHuman InheritanceTraits

Questions

A.Whatobservationscanbe made about the collectedand charteddata?

Thechart data does not correlate much with the data collected in thetable, however,

thereis a general distinct pattern on the genetic traits of human beings.

B. Areanytwopeople exactlythe same? If so,howclosely aretheyrelated?

Indeedthe data indicates two cases of paired persons who are identical.This is because

theyhad similar Genetic inheritance traits and that they are bothhomo-zygote twins.

C. Isyourhypothesissupportedbythefindings?Whatstatisticaltoolmighthelpyoutomake

Thisdecision?

Inthe analysis of these genetic characteristics, various tests werecarried out.

Inparticular the z-test was instrumental in supporting my geneticinheritance hypothesis

D.InthetotalsthatyourecordedinTable1,didyoufindthatthenumberofdominantphenotypes

weregreaterthan, equal to,or less than the recessivephenotypes?

Afterthe tabulation of the results in the table, the results indicatedthat dominant

Phenotypescharacteristics. Exceeded the recessive phenotypes.

E. Canyouexplainwhatpossiblegenotypesaresuggestedbythispattern?Doesthisvary

Bytrait?

Inthis case, the pattern depicts the possibility of a dominant allelein a heterozygous

genotypeor homozygous. In this case, it means that there is no completedominance

nodominant phenotype in the heterozygous or in the homozygotecondition. This further

meansthat no single allele has masked the other and therefore no change ininherited traits.

F. Wouldyouexpectthisoutcome?Whyorwhynot?

Ofcourse yes. Although in a normal situation, one allele in aheterozygous genotype state

maskscompletely the effects of the homozygote genotype. The allele that ismasked is said

tobe recessive to the dominant. However, in the above case no singleallele has completely

maskedthe other

G.Howwouldchangingthelevelofthemappedtraitsaffectthechart?Forinstance,iftheallelesformale or femalewereontheouterrim of the chart, ratherthaninthemiddle,howwouldthepatternobserveddifferfromFigure10-1?

Therewould be no change or effect because the same linked pattern wouldnot be affected by the

changedmapping of the female or male alleles on the outer rim of the chart

H.Listseveralother traitsthathumans havethataregovernedbygenetics.

Thereare various physical and internal traits that humans inherit due tothe genetic makeup of

theirparents. As such different individuals’ develops different traitsfrom the inherited dominant

alleles.Examples of these traits can be seen in hairline shape,colorblindness, tongue rolling,

detachedand attached earlobes, dimples, freckles, curvy hair, allergies andhandclapping.

Inother cases others inherit medical complications such as sickle cellanemia, hemophilia and

others.

I. Wouldyourdatavaryif youwenttoanother part of the world,forinstance,China?

Sure.There would be great variation in the genetic components-alleles asthey differ from

onepopulation to another

J. Whymightcollecteddatashowdifferentpatternsfordifferentculturalpopulations?

Inmost cases, the rate and frequency of genotype alleles may show adifferent pattern. This

ismainly because other factors such as geographic region and partnersinvolved in siring may

producea different pattern.

K. Wouldyouexpectthatthepatternwouldbedifferentifcollected100yearsagoinsteadof

today?Whyorwhynot?

Sure,there would be a great different if the same studies were done 100years ago instead of

today.This is because the frequency of alleles which are responsible formost genetic traits in human

beingsare influenced or changed by various forces which alters thedistribution of the alleles in

individuals.Although not physically seen, there is an internal evolution thatgoes on as individuals

Interbreed.In some cases the selection of the breeding partner, mutation,migration, genetic drift

amongothers are the main changes that would give a different pattern asthe one in the table.

L. Ifyouhadpercentagesofdominantandrecessivegenespresentforthetotalnumberofallelesofatraitfortheentireworld,wouldyouexpectthatpercentagetochangeover100years?Whyorwhynot?

Sure.The percentage and total number of allele would change over 100 yearsdue to several factors

Suchas migration, mutation, mating and the population size. This isbecause change in allele

frequencyalso changes with population diversity, change in geographic regionand selectivity

inmating partners and genetic mutation during the formation of a newoffspring.

Exercise2:HumanChromosomesandtheHuman

GenomeProject

Results

Reporton yourfindings.Yourreportshould be limitedtoa pagein lengthand mayincorporatethe outline of researchpointsabove.

Inthis case the experiment was similar in idea to the above caseconcerning the recessive and dominant allele. The effect of dominantand recessive alleles extends their effects to the Chromosomes inwhich individual traits are determined. Traits that correspond to thedominant allele are referred to us the dominant traits while therespective ‘hidden’ or ‘masked’ alleles are known asrecessive traits. However, the dominance effect of alleles is notinherited and changed with time, mutation and breeding. Dominantallele can lead to a heterozygous or a homozygous state. In thisexercise, the ratio of dominant alleles exceeded the number ofrecessive alleles. This explains why different individuals havedifferent character traits within a population based on their genesin the chromosomes. However, this changes from one population to theother.

Questions

  1. What is the purpose of this exercise?

Thisexercise was instrumental in facilitating more insightfulunderstanding on the genetic make ups

andhow such genetics determines individual traits. In addition, theexercise was significant in the understanding of how certain diseasesare genetically tied and how treatment can be undertaken.

B. Whatistheprognosisongeneticdiseasesinthefuture?Doyoubelievethatmicrosurgeryto“fixchromosomalaberrationswillsomedaypreventthediseasesthatarelistedintheListofGeneticallyMediatedDiseases in Humans?

Thegreat research studies undertaken, through projects such as the HumanGenome

projectand chromosomes will have instrumental impacts in the invention ofmicrosurgery where

DNAsurgery will be done to change the genetic composition. Basednumerous prognosis done

chromosomalaberration will be possible though great challenges might beencountered.

However,just the same way scientists have been able to invent GeneticallyModified Organisms

inplants, there is a possibility of microsurgery on animals and humanbeings alike.

LaboratorySummary

Whathaveyoulearnedfromdoingthis laboratory?

Thisexercise was really helpful in in the understanding of variousaspects of genetics. In particular, the information gathered on howgenetics influence human traits have been more helpful. In addition,the laboratory exercise has been insightful in understanding thegenetic traits of different population, how forces like mutation,migration, partner selection and the frequency of alleles affects thegenetic traits. Far from this, the laboratory exercise did enhancemore understanding on gathering data, analyzing it and interpretingthe results to get a prognosis trend of a particular trait or diseaseamong individuals.

References

http://learn.genetics.utah.edu/content/inheritance/activities/pdfs/Inherited%20Human%20Traits%20Quick%20Referenc e_Public.pdf

GriffithsAJF, Gelbart WM, Miller JH, et al. &quotGeneInteraction Leads to Modified Dihybrid Ratios.&quot

ModernGenetic Analysis.New York: W. H. Freeman &amp Company. (1999).

Rostand,J and Tétry, A . “AnAtlas of .”HutchinsonScientific &amp Technical, London. (1964).

VictorK. McElheny. “Drawingthe Map of Life: Inside the Human Genome Project.”BasicBooks. (2010).

Copyright© 2008 byMargaretE. Vorndam,1413 CountyRoad671, Rye,CO81069

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