Human Traits and Heredity

Shanghai Dajing Middle School Junying Zhou

As the saying goes “ like father ,like son ”Do you look like your parents?

The tendency of an individual to resemble his parents called Heredity.

That means a few traits are passed down from one generation to another.

traits Dominant traits

number Recessive trait

number

Forehead hairstyle

前额发突

Widow’s peak

三角形突出形No widow’s peak 较平整形

Earlobe

耳垂Free earlobe

游离耳垂Attached earlobe 附着耳垂

Tongue rolling ability 卷舌

Roller 可卷称“ U” 形

Non roller 不会卷起

Thumb

拇指Can’t bend

不能弯曲Can bend

能弯成 60 度The way of claspi

ng fingers

手指嵌合

Inlay(the left thumb on top)

手指嵌入（左手拇指在上）

Not inlay(the right thumb on top) 手指不嵌入（右手拇指

在上）

Survey of human traits

The Father of Genetic——Gregor Mendel

Gregor Mendel was born in 1822 to peasant parents .

In 1851, Mendel was sent to the University of Vienna to study science and mathematics. Mendal published his findings in 1865,

but no one valued his theory until 1900,

after he had passed away for 16 years.

The cross-pollination produce

Observe the male parts and female parts of a flower 辨别一朵花中雌蕊和雄蕊Carefully cut off the male parts of one flower and female parts of another flower 剪去一朵花的雄蕊和另一朵花的雌蕊

dusting the pollens from one flower onto another flower 把一朵花的花粉涂到另一朵花上

P—parentalgeneration

True breeding green pods

True breedingyellow pods

×

F1—first generation

All green

F2—second generation

3/4 green 1/4 yellow

Mendel’s Law of Segregation

Interpretation of Mendel’s Law of Segregation

There are different forms of genes.These different forms of a gene are called alleles.同一基因的不同表现形式称为等位基因。

When the two alleles of a pair are different, one is dominant and the other is recessive. 一对等位基因中一个是显性的另一个是隐性的。

P GG gg×

F1

F23/4 green

1/4 yellow

GG Gg

Gg gg

G

g

G g

Interpretation of Mendel’s Law of Segregation

gGGg

Exercises The allele of the thumb,Can’t bend(A) is dominant to can bend (a).

Father:AA Mother:aa

? The child Aa

1.

Exercises

Father: Aa

? The child

Mother: Aa2.

3/4 AA /Aa 1/4aa

3. Father:Aa

The child: aa

? Mother

Summary

Today we just learn the “tip of the iceberg” when it comes to genetic research, there are many more to explore.

Thank you