Intro to GeneticsMr. Mah

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Think for a second about the most crazy thing you have ever

seen…

when something like THIS could be possible…

Imagine in the future…

The future is now…

How did the scientists do

it?

INTRO TO GENETICS

GENETICS:the study of how traits are passed

from one generation to the next

TRAIT:a characteristic

Examples:Plant size, seed color, pod

shape

GENE:the factors that control traits

(found on chromosomes)

*can be passed down from one generation to another

CHROMOSOME:tightly coiled strands of DNA stored in the

NUCLEUS

* genes = segments of chromosomes

ALLELES:different forms

of a gene

GENESEach feature of the pea plants is controlled by a

gene. It may have a gene that controls its color, another for size and another for shape.

Above you see chromosomes. The circled area is a gene on chromosome #22. The absence of this gene causes velo-cardio-facial syndrome (VCFS)

which may cause ADD and mental illness

ALLELESEach gene comes in different forms called alleles,

so the gene that controls flower color may come in two alleles: purple and white.

GREGOR MENDEL• The “father” of genetics• Lived from 1822-1884• Austrian Monk• Published his work in

1866, but no one took him seriously until 1900.

• Studied Pea Plants!

MENDEL’S EXPERIMENTS

Mendel experimented with 7 different characteristics

How can we determine what the offspring are

going to be?

DOMINANT traits:allele that is always

expressed (TT or Tt = tall)

RECESSIVE traitsallele that is expressed

only when homozygous(tt = short)

HOMOZYGOUS organism with two identical alleles for

the same trait(TT or tt)

HETEROZYGOUS organism with two different alleles for

the same trait(Tt)

GENOTYPEthe genetic makeup

(TT, TtHh)*depends on the genes you

inherit

PHENOTYPEphysical

characteristics(Tall, Brown)

*depends on genes BUT can be affected by environmental factors

A child has brown hair and brown eyes. His father has brown hair and blue eyes. His mother has red hair and brown eyes. The best explanation for the child having brown hair and brown eyes is that

(A) A gene mutation occurred that resulted in brown hair and brown eyes

(B) Gene expression must change in each generation so evolution can occur

(C) The child received genetic information from each parent

(D) Cells from his mother’s eyes were present in the fertilized egg

A child has brown hair and brown eyes. His father has brown hair and blue eyes. His mother has red hair and brown eyes. The best explanation for the child having brown hair and brown eyes is that

(A) A gene mutation occurred that resulted in brown hair and brown eyes

(B) Gene expression must change in each generation so evolution can occur

(C) The child received genetic information from each parent (D) Cells from his mother’s eyes were present in the fertilized egg

In a particular variety of corn, the kernels turn red when exposed to sunlight. In the absence of sunlight, the kernels remain yellow. Based on this information, it can be concluded that the color of these corn kernels is due to

(A) A different type of DNA that is produced when sunlight is present

(B) A different species of corn that is produced in sunlight

(C) The effect of sunlight on the number of chromosomes inherited

(D)The effect of environment on gene expression

In a particular variety of corn, the kernels turn red when exposed to sunlight. In the absence of sunlight, the kernels remain yellow. Based on this information, it can be concluded that the color of these corn kernels is due to

(A) A different type of DNA that is produced when sunlight is present

(B) A different species of corn that is produced in sunlight

(C) The effect of sunlight on the number of chromosomes inherited

(D)The effect of environment on gene expression