Mendel’s Lab Work Essay Assignment Paper

Mendel’s lab work: Gregor Mendel used pea plants to study heredity in a series of experiments. Mendel worked by carefully observing and recording traits in successive generations of plants. Knowledge about DNA and chromosomes came later.

This lab will apply genetic laws to human inheritance using Punnett squares. Mendel’s Lab Work Essay Assignment Paper

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Recall that DNA is wound tightly into chromosomes. Cells with only one set of chromosomes, such as sex cells, are haploid. When two haploid cells fuse during fertilization, a diploid zygote with two full sets of chromosomes is formed. Most cells of a mature individual are diploid.

Mendel’s lab work

Homologous chromosomes have the same genes, but they might have different versions (alleles) of those genes. Diploid cells have two alleles for each gene. These alleles might be identical (gene A) or different (gene B). Each gene’s locus is its location on a chromosome.

Human traits come through dominant or recessive inheritance. For example, the cystic fibrosis traits carried by a dominant allele are always expressed, even if the recessive gene is present (FF or Ff). The recessive is only expressed when two copies of the recessive allele are present (ff). Mendel’s Lab Work Essay Assignment Paper

		Mother: Healthy carrier
		F	f
Father: Healthy carrier	F	FF Healthy non-carrier	FfHealthy carrier
	f	FfHealthy carrier	FFAffected

Human gender is carried on the X and Y chromosomes. Females are XX and males are XY. Heredity traits such as color blindness, which is the inability to distinguish among some colors, are carried on the X chromosome (Xc). The presence of one normal XC will allow normal vision.

In this next set of exercises, you will determine the genotypes of the parents by considering the inheritance patterns of traits in their children. The following is a table of the phenotypes of the family members: Mendel’s Lab Work Essay Assignment Paper

	Phenotype	Alleles
Parents
Mother	Not color blindFreckles Type B blood	Xc XCFf IBi
Father	Color blindNo freckles Type A blood	XcYFf IAi
Children
Abby	Color blindFreckles	Xc XcFf or ff
Brady	Not color blindNo freckles	XCYff
Carly	Not color blindNo freckles	Xc XCff
Dennis	Color blindFreckles	XcYFf or ff

Exercise 1: Color Blindness

Using the alleles XC (not color blind) and Xc (color blind), distribute the gametes from each parent to the outside of the Punnett square. Drag and drop the child with the correct phenotype to the box within the Punnett square that has the corresponding genotype that would occur from the fusion of egg and sperm as indicated by your placement of the gametes. Mendel’s Lab Work Essay Assignment Paper

 

Exercise 2: Freckles

Freckles are groups of cells on the skin that produce the pigment melanin, often in response to exposure to ultraviolet (UV) light. The gene for freckles is inherited in a dominant/recessive pattern. A person carrying even a single copy of the dominant allele (F) will have freckles. A person who is homozygous recessive (ff) will have no freckles. Mendel’s Lab Work Essay Assignment Paper

Using the alleles F (freckles) and f (no freckles), distribute the gametes from each parent to the outside of the Punnett square. Drag and drop the child with the correct phenotype to the box within the Punnett square that has the corresponding genotype that would occur from the fusion of egg and sperm as indicated by your placement of the gametes.

 

Exercise 3: Blood Type

In codominance, more than one allele encodes a functional protein. IA codes for A markers on red blood cells. IB codes for B markers. i codes for neither A nor B markers, no markers. Human blood types IAIA and IAi are Type A blood. IBIB and IBi are Type B blood. IAIB is a codominant expression of alleles and results in type AB blood. ii is Type O blood. Mendel’s Lab Work Essay Assignment Paper

Genotypes	Phenotypes
IAIA orIAi	Blood Type A
IBIB orIBi	Blood Type B
IAIB	Blood Type AB
ii	Blood Type O

These parents have a child with Type O (ii) blood. Investigate the possible genotypes for each parent to determine how this genetic outcome would occur. Why must each parent carry the i allele to have a child with Type O blood? Drag and drop the gametes from each parent to the outside of the Punnett square. Drag and drop the corresponding zygote to each block of the Punnett square. Mendel’s Lab Work Essay Assignment Paper

 

Reference

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Audesirk, T., Audesirk, G., & Byers, B. E. (2008). Biology: Life on earth with physiology. Upper Saddle River, NJ: Prentice Hall.M. Mendel’s Lab Work Essay Assignment Paper