Question

BIOL 105 PRINCIPLES OF GENETICS LABORATORY 6 Deffators and examples 1) Mendel's First Law is often referred to as the Law of Segregation. Create an example to illustrate it and use Chi-Square to verify your results. Detfintion & exompes 2) Mendel's Second Law is often referred to as the Law of Independent Assortment, example to illustrate it and Chi-Square to verify your results. -Dettorit was sexom 3) Explain and demonstrate how a dihybrid test cross can be used to determine if autosomal linkage exists. Deltinches. 4) Explain and demonstrate how the distance between loci on a chromosome affects the amount of cross over, and therefore the recombination frequency. Law of segregation - Derintions - exampie scecete YY yellow yy Green Law of yellow vyy v
need examples and word problem to go with it.

Answer 1

1) Mendel's first law was the law of segregation. It states that only one gene copied into the gamete , that which is randomly selected.

The Chi-square or the punnet square is used to predict the genotype and phenotype of an organism.

In the Mendel's model, there are two copies of the gene in an individual

For example, the YY gene stands for yellow seed and Y shows dominance. yy on the other hand is recessive trait (green seed). Both of them are homozygous. On the other hand, YY is heterogeneous.

When parents of homogeneous genes YY and yy are crossed, the offspring will result in heterogeneous gene.

Y+ y= Yy

These heterogeneous offsprings when pollinated,it will give offsprings in the ratio 3:1.

	Y	y
Y	YY(yellow)	YY(yellow)
y	Yy(yellow)	YY(green)

2) law of independent assortment states that the allele in two different genes does not affect each other.

For example , let us take an example of pea colour and pea shape, one with yellow round seed(YYRR) and another of green wrinkled seeds(yyrr).

From the law of segregation we understand that the first generation of offspring is YyRr. The second generation of offspring ,gives crossing with heterogeneous genotype which gives Offsprings in the ratio 9:3:3:1.

YyRr ×YyRr

	YR	yR	Yr	yr
YR	YYRR(yellow round)	YyRR ( yellow round)	YYRr (yellow round)	YyRr(yellow round)
yR	YyRr(Yellow round)	yyRR (green round)	YyRr (yellow round)	yyRr (green round)
Yr	YYRr (Yellow round)	YyRr (yellow round)	YYrr (yellow wrinkled)	Yyrr ( yellow wrinkled)
yr	YyRr (Yellow round)	yyRr ( green round)	Yyrr (yellow wrinkled)	yyrr ( green wrinkled)

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