LaunchWhat does it mean to be homozygous

recessive? *Use scientific language and terms*

Complete the punnett using ratios for genotype and phenotypes:

Why in a normal human being do you only get one allele from each parent?

X Y

XX

Cross a homozygous dominant with a recessive (for height where T is dominant and tall).

Find the genotype and the phenotype

Cross a heterozygote with a recessive (for height where T is dominant and tall).

Find the genotype and the phenotype

Cross a heterozygote with another heterozygote (for skin color where Black is B, b = white).

Find the genotype and the phenotype

Cross a heterozygote with another heterozygote (for nose size where big nose is N and small nose is n).

Find the genotype and the phenotype

a trait that is found on either the X or Y chromosome

Examples include baldness and color blindness

Sex Linked Trait

Sex linked traits are more likely to affect males

Sex Linked Trait

Hemophilia is a disease where your blood doesn’t clot.

Hemophilia is an example of a sex linked trait.

Hemophilia

Hemophilia only occurs when all of the X chromosomes have a copy of the recessive gene.

XHXh:female carrier XhXh:female

hemophiliac XHY:normal male XhY:hemophiliac

male

chart that shows the relationships within a family

PEDIGREE

Pedigree BasicsMales are squares, females are circles

Shaded figures represent individuals with the trait

Generations are numbered with roman numerals (I, II, II, IV) from top to bottom

Klinefelter SyndromeMales with Klinefelter syndrome have two X

chromosomes, and one Y

X Y XX

0

XXX XXY

X,0 Y,0

Klinefelter SyndromeHave male genitalia and internal ducts, but

underdeveloped testesDo not produce spermSlight enlargement of the breasts47,XXY1 out of every 500 male births

Turner SyndromePeople with Turner Syndrome only receive

one sex chromosome, an X.

X Y XX

0

XXX XXY

X,0 Y,0

Turner SyndromeHas female external genitaliaUnderdeveloped ovariesShort (under 5 feet)Webbed NeckBroad, Shield-like chest45,X1 out of every 3000 female births